Stabilized polyolefin compositions

ABSTRACT

Disclosed are compositions comprising antioxidants and stabilizers, such as, acid scavengers or organic phosphorus stabilizers, and optionally further comprising co-stabilizers. The disclosed compositions are useful as stabilizers for polyolefins and other polymeric materials. The disclosed compositions and methods generally provide longer shelf lifes and better oxidative resistance to materials than currently available antioxidants.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/789,832, filed May 28, 2010 now U.S. Pat. No. 8,008,423, which is acontinuation of U.S. application Ser. No. 11/293,844, filed Dec. 2, 2005now U.S. Pat. No. 7,902,317, which claims the benefit of U.S.Provisional Application No. 60/633,196, filed on Dec. 3, 2004. Theentire teachings of the above applications are incorporated herein byreference.

BACKGROUND OF THE INVENTION

Antioxidants are employed to prevent oxidation in a wide range ofmaterials, for example, plastics, elastomers, lubricants, petroleumbased products (lubricants, gasoline, aviation fuels, and engine oils),cooking oil, cosmetics, processed food products, and the like. Whilemany antioxidants exist, there is a continuing need for new antioxidantsthat have improved properties.

SUMMARY OF THE INVENTION

The present invention relates to compositions comprising antioxidantsand stabilizers, such as, acid scavengers or organic phosphorusstabilizers and optionally further comprising co-stabilizers. Thesecompositions are useful as stabilizers for polyolefins and otherpolymeric materials.

In one embodiment the present invention is a composition comprising anantioxidant, and at least one additive selected from the groupconsisting of a phosphorus stabilizer (e.g., a phosphate or phosphitestabilizer), an acid stabilizer and a co-stabilizer.

In another embodiment, the present invention is a polyolefin compositioncomprising a polyolefin or a mixture of polyolefins, an antioxidant, andat least one additive selected from the group consisting of a phosphorusstabilizer (e.g., a phosphate or phosphite stabilizer), an acidstabilizer and a co-stabilizer.

In yet another embodiment, the present invention is a method ofpreventing oxidation in a polyolefin or a mixture of polyolefinscomprising combining the polyolefin or mixture of polyolefins with anantioxidant, and at least one additive selected from the groupconsisting of a phosphorus stabilizer (e.g., a phosphate or phosphitestabilizer), an acid stabilizer and a co-stabilizer.

The compositions and methods of the present invention generally providelonger shelf life and better oxidative resistance to materials thancurrently available antioxidants.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1, is a comparison of an oxidative induction time (OIT) ofpolypropylene in combination with one embodiment of the invention,namely, benzenepropanamide,3,5-bis(1,1-dimethylethyl)-4-hydroxy-N-(4-hydroxyphenyl): i) alone, ii)in combination with calcium stearate (CasS), iii) in combination withcalcium stearate and phosphate (P) and iv) in combination with calciumsulfide, phosphite and zinc oxide (Z).

FIG. 2 is a comparison of the Melt flow Index (MFI) of polypropylene incombination with one embodiment of the invention, namely,benzenepropanamide,3,5-bis(1,1-dimethylethyl)-4-hydroxy-N-(4-hydroxyphenyl): i) alone, ii)in combination with calcium stearate (CasS), iii) in combination withcalcium stearate and phosphate (P) and iv) in combination with calciumsulfide, phosphite and zinc oxide (Z).

DETAILED DESCRIPTION OF THE INVENTION

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

The present invention relates to compositions, such as, polymerprocessing formulations involving i) antioxidants described inProvisional Patent Application Nos. 60/632,893, 60/633,197, 60/633,252,60/633,196, 60/665,638 and 60/655,169, U.S. patent application Ser. Nos.11/184,724 (U.S. Patent Publication No. 2006/0041094), Ser. No.11/184,716 (U.S. Patent Publication No. 2006/0041087), Ser. No.11/040,193 (U.S. Pat. No. 7,323,511), Ser. No. 10/761,933 (U.S. Pat. No.7,595,074), Ser. No. 10/408,679 (U.S. Pat. No. 7,223,432) and Ser. No.10/761,933 (U.S. Pat. No. 7,595,074), Provisional Patent Application No.60/731,125, filed Oct. 27, 2005, Title: Macromolecular Antioxidants AndPolymeric Macromolecular Antioxidants, by Ashok L. Cholli, et al.Provisional patent application No. 60/731,021, filed Oct. 27, 2005,Title: Macromolecular Antioxidants Based On Sterically Hindered Phenolsand Phosphites, by Ashok L. Cholli, et al. PCT Patent Application Nos.PCT/US2005/001948 (WO 2005/070974), PCT/US2005/001946 (WO 2005/071005)and PCT/US03/10782 (WO 2003/087260), the entire contents of each ofwhich are incorporated herein by reference, along with ii) stabilizerssuch as acid scavengers or organic phosphorus stabilizers and/or iii)co-stabilizers used in polyolefins and other polymeric materials.

In one embodiment, the antioxidants which are suitable for use in thecompositions and methods of the present invention include but are notlimited to polyalkyl phenol based antioxidants, sterically hinderedphenol based antioxidants, sterically hindered phenol basedmacromolecular antioxidants, nitrogen and hindered phenol containingdual functional macromolecular antioxidants, alkylated macromolecularantioxidants, sterically hindered phenol and phosphite basedmacromolecular antioxidants.

In one embodiment, the antioxidants which are suitable for use in thecompositions and methods of the present invention include antioxidantpolymers which comprises repeat units that include one or both ofStructural Formulas (I) and (II):

where:

R is —H or a substituted or unsubstituted alkyl, substituted orunsubstituted acyl or substituted or unsubstituted aryl group;

Ring A is substituted with at least one tert-butyl group or substitutedor unsubstituted n-alkoxycarbonyl group, and optionally one or moregroups selected from the group consisting of —OH, —NH, —SH, asubstituted or unsubstituted alkyl or aryl group, and a substituted orunsubstituted alkoxycarbonyl group;

Ring B is substituted with at least one —H and at least one tert-butylgroup or substituted or unsubstituted n-alkoxycarbonyl group andoptionally one or more groups selected from the group consisting of —OH,—NH, —SH, a substituted or unsubstituted alkyl or aryl group, and asubstituted or unsubstituted alkoxycarbonyl group;

n is an integer equal to or greater than 2; and

p is an integer equal to or greater than 0.

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention include polymerswith repeat units represented by one or both of Structural Formulas(III) and (IV):

where Rings A and B are substituted as described above and n and p areas defined above.

Preferably, Ring A and Ring B in Structural Formulas (I) to (IV) areeach substituted with at least one tert-butyl group.

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention include polymerswith repeat units represented by one or more of Structural Formulas(Va), (Vb), (Vc), (VIa), (VIb) and (VIc):

where R₁, R₂ and R₃ are independently selected from the group consistingof —H, —OH, —NH, —SH, a substituted or unsubstituted alkyl or asubstituted or unsubstituted aryl group, and a substituted orunsubstituted alkoxycarbonyl group, provided that at least one of R₁, R₂and R₃ is a tert-butyl group; and j and k are independently integers ofzero or greater, such that the sum of j and k is equal to or greaterthan 2.

In a particular embodiment, R is —H or —CH₃; R₂ is —H, —OH, or asubstituted or unsubstituted alkyl group; or both.

Specific examples of repeat units included in polymers which aresuitable for use in the compositions and methods of the presentinvention are represented by one of the following structural formulas:

Antioxidant polymers as described immediately above which are suitablefor use in the compositions and methods of the present invention havetwo or more repeat units, preferably greater than about five repeatunits. The molecular weight of the polymers disclosed above is generallyselected to be appropriate for the desired application. Typically, themolecular weight is greater than about 500 atomic mass units (amu) andless than about 2,000,000 amu, greater than about 1000 amu and less thanabout 100,000, greater than about 2,000 amu and less than about 10,000,or greater than about 2,000 amu and less than about 5,000 amu.

Antioxidant polymers as described immediately above which are suitablefor use in the compositions and methods of the present invention can beeither homopolymers or copolymers. A copolymer preferably contains twoor more or three or more different repeating monomer units, each ofwhich has varying or identical antioxidant properties. The identity ofthe repeat units in a copolymer can be chosen to modify the antioxidantproperties of the polymer as a whole, thereby giving a polymer withtunable properties. The second, third and/or further repeat units in acopolymer can be either a synthetic or natural antioxidant.

Antioxidant polymers as described immediately above which are suitablefor use in the compositions and methods of the present invention aretypically insoluble in aqueous media. The solubility of the antioxidantpolymers in non-aqueous media (e.g., oils) depends upon the molecularweight of the polymer, such that high molecular weight polymers aretypically sparingly soluble in non-aqueous media. When an antioxidantpolymer of the invention is insoluble in a particular medium orsubstrate, it is preferably well-mixed with that medium or substrate.

Antioxidant polymers as described immediately above which are suitablefor use in the compositions and methods of the present invention can bebranched or linear, but are preferably linear. Branched antioxidantpolymers can only be formed from benzene molecules having three or fewersubstituents (e.g., three or more hydrogen atoms), as in StructuralFormulas (XX), (XXI) and (XXIV).

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention include polymerswith repeat units represented by one or both of Structural Formulas (I)and (II):

where:

R is —H or a substituted or unsubstituted alkyl, acyl or aryl group;

Ring A is substituted with at least one tert-butyl group,1-ethenyl-2-carboxylic acid group or ester thereof, substituted orunsubstituted alkylenedioxy group, or substituted or unsubstitutedn-alkoxycarbonyl group and zero, one or more additional functionalgroups;

Ring B is substituted with at least one —H and at least one tert-butylgroup, 1-ethenyl-2-carboxylic acid group or ester thereof, substitutedor unsubstituted alkylenedioxy group, or substituted or unsubstitutedn-alkoxycarbonyl group and zero, one or more additional functionalgroups;

n is an integer equal to or greater than 2; and

p is an integer equal to or greater than 0,

where the polymer includes two or more repeat units represented by oneor both of Structural Formulas (I) and (II) that are directly connectedby a C—C or C—O—C bond between benzene rings.

Polymers as described immediately above which are suitable for use inthe compositions and methods of the present invention that do notinclude any repeat units represented by Structural Formula (I) arepreferably substituted on Ring B with one or more hydroxyl or acyloxygroups.

Repeat units of the antioxidant polymers as described immediately abovewhich are suitable for use in the compositions and methods of thepresent invention include substituted benzene molecules. These benzenemolecules are typically based on phenol or a phenol derivative, suchthat they have at least one hydroxyl, ester or ether functional group.Preferably, the benzene molecules have a hydroxyl group. The hydroxylgroup is not restricted to being a free hydroxyl group, and the hydroxylgroup can be protected or have a cleavable group attached to it (e.g.,an ester group). Such cleavable groups can be released under certainconditions (e.g., changes in pH), with a desired shelf life or with atime-controlled release (e.g., measured by the half-life), which allowsone to control where and/or when an antioxidant polymer is able to exertits antioxidant effect.

Substituted benzene repeat units of an antioxidant polymer as describedimmediately above which are suitable for use in the compositions andmethods of the present invention are also typically substituted with abulky alkyl group, a 1-ethenyl-2-carboxylic acid group, a substituted orunsubstituted alkylenedioxy group, or an n-alkoxycarbonyl group.Preferably, the benzene monomers are substituted with a bulky alkylgroup. More preferably, the bulky alkyl group is located ortho or metato a hydroxyl group on the benzene ring. A “bulky alkyl group” isdefined herein as an alkyl group that is branched alpha- or beta- to thebenzene ring. Preferably, the alkyl group is branched alpha to thebenzene ring. More preferably, the alkyl group is branched twice alphato the benzene ring (i.e., to form an alpha-tertiary carbon), such as ina tert-butyl group. Other examples of bulky alkyl groups includeisopropyl, 2-butyl, 3-pentyl, 1,1-dimethylpropyl, 1-ethyl-1-methylpropyland 1,1-diethylpropyl. The bulky alkyl groups are preferablyunsubstituted, but they can be substituted with a functional group thatdoes not interfere with the antioxidant activity of the molecule or thepolymer.

Substituted benzene repeat units that are substituted with a substitutedor unsubstituted alkylenedioxy group typically have an unsubstitutedalkylenedioxy group. Substituted alkylenedioxy groups are also suitable,although the substituents should not interfere with the antioxidantactivity of the molecule or the polymer. Typically, an alkylenedioxygroup is a lower alkylenedioxy group, such as a methylenedioxy group oran ethylenedioxy group. A methylenedioxy group is preferred (as insesamol).

Straight chained alkoxycarbonyl groups typically have an alkyl chain ofone to sixteen carbon atoms, and include methoxycarbonyl,ethoxycarbonyl, n-propoxycarbonyl, n-butoxycarbonyl andn-pentoxycarbonyl. n-propoxycarbonyl is a preferred group. Similar tothe bulky alkyl groups, n-alkoxycarbonyl groups are optionallysubstituted with a functional group that does not interfere with theantioxidant activity of the molecule or the polymer. Alkoxycarbonylgroups can also be present in their hydrolyzed form, namely as carboxygroups or carboxylic acid groups.

In substituted benzene repeat units having a 1-ethenyl-2-carboxylic acidgroup or an ester thereof, the 1-carbon (i.e., the carbon distal fromthe carboxylic acid moiety) is attached to the benzene ring.

In addition to the substituents named above, substituted benzene repeatunits can have additional functional groups as substituents. Forexample, the additional functional groups can be selected from the groupconsisting of —OH, —NH, —SH, a substituted or unsubstituted alkyl oraryl group, a substituted or unsubstituted alkoxycarbonyl group, asubstituted or unsubstituted alkoxy group and a saturated or unsaturatedcarboxylic acid group. Typically, the additional functional groups areselected from the group consisting of —OH, a substituted orunsubstituted alkoxy group and a saturated or unsaturated carboxylicacid group.

Preferably, Ring A and Ring B in Structural Formulas (I) to (IV) areeach substituted with at least one tert-butyl group.

Further, specific examples of repeat units included in polymers whichare suitable for use in the compositions and methods of the presentinvention are represented by one of the following structural formulas:

Although Structural Formulas (XI), (XVI), (XVII) and (XVIII) arerepresented as having a propoxycarbonyl substituent, this group cangenerally be replaced with a different C₁-C₁₆ n-alkoxycarbonyl group orcan be a carboxylate group.

A particular polymer suitable for use in the methods and compositions ofthe present invention is poly(2-tert-butyl-4-hydroxyanisole).

Antioxidant polymers as described immediately above which are suitablefor use in the methods and compositions of the present invention havetwo or more repeat units, preferably greater than about five repeatunits. The molecular weight of the polymers disclosed herein isgenerally selected to be appropriate for the desired application.Typically, the molecular weight is greater than about 500 atomic massunits (amu) and less than about 2,000,000 amu, greater than about 1000amu and less than about 100,000, greater than about 2,000 amu and lessthan about 10,000 amu, or greater than about 2,000 amu and less thanabout 5,000 amu.

Antioxidant polymers as described immediately above which are suitablefor use in the methods and compositions of the present invention can beeither homopolymers or copolymers. A copolymer preferably contains twoor more or three or more different repeating monomer units, each ofwhich has varying or identical antioxidant properties (includingmonomers having no antioxidant activity). The identity of the repeatunits in a copolymer can be chosen to modify the antioxidant propertiesof the polymer as a whole, thereby giving a polymer with tunableproperties. The second, third and/or further repeat units in a copolymercan be either a synthetic or natural antioxidant. In one example, acomposition of the invention includes one or more homopolymers and oneor more copolymers (e.g., in a blend). Preferably, both homopolymers andcopolymers include two or more substituted benzene repeat units that aredirectly connected by a C—C or C—O—C bond. Preferably, at least 50%,such as at least 70%, for example, at least 80%, but preferably about100% of the repeat units in a copolymer are substituted benzene repeatunits directly connected by a C—C or C—O—C bond.

Examples of copolymers include poly(TBHQ-co-propyl gallate),poly(TBHQ-co-BHA), poly(TBHQ-co-sesamol), poly(BHA-co-sesamol),poly(propyl gallate-co-sesamol) and poly(BHA-co-propyl gallate). Theratio of one monomer to another, on a molar basis, is typically about100:1 to about 1:100, such as about 10:1 to about 1:10, for example,about 2:1 to about 1:2. In one example, the ratio of monomers is about1:1.

Antioxidant polymers as described immediately above which are suitablefor use in the methods and compositions of the present invention aretypically insoluble in aqueous media, although certain polymers ofgallic acid and its esters are water soluble. The solubility of theantioxidant polymers in non-aqueous media (e.g., oils) depends upon themolecular weight of the polymer, such that high molecular weightpolymers are typically sparingly soluble in non-aqueous media. When anantioxidant polymer of the invention is insoluble in a particular mediumor substrate, it is preferably well-mixed with that medium or substrate.

Antioxidant polymers as described immediately above which are suitablefor use in the methods and compositions of the present invention can bebranched or linear, but are preferably linear. Branched antioxidantpolymers can only be formed from benzene molecules having three or fewersubstituents (e.g., three or more hydrogen atoms), as in StructuralFormulas (XX), (XXI) and (XXIV).

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention include apolyalkylphenol antioxidant represented by Structural Formula U.

In Structural Formula U, n is an integer equal or greater than 2. R is aC1-C10 alkyl group, an aryl group, or a benzyl group. Typically, R is atertiary alkyl group, or in preferred embodiments, a tertiary butylgroup.

Repeat units of the antioxidant polymers as described immediately abovewhich are suitable for use in the compositions and methods of thepresent invention include substituted benzene molecules. These benzenemolecules are typically based on phenol or a phenol derivative, suchthat they have at least one hydroxyl or ether functional group.Preferably, the benzene molecules have a hydroxyl group. The hydroxylgroup can be a free hydroxyl group and can be protected or have acleavable group attached to it (e.g., an ester group). Such cleavablegroups can be released under certain conditions (e.g., changes in pH),with a desired shelf life or with a time-controlled release (e.g.,measured by the half-life), which allows one to control where and/orwhen an antioxidant polymer can exert its antioxidant effect. The repeatunits can also include analogous thiophenol and aniline derivatives,e.g., where the phenol —OH can be replaced by —SH, —NH—, and the like.

Substituted benzene repeat units of an antioxidant polymer as describedimmediately above which are suitable for use in the compositions andmethods of the present invention are also typically substituted with abulky alkyl group or an n-alkoxycarbonyl group. Preferably, the benzenemonomers are substituted with a bulky alkyl group. More preferably, thebulky alkyl group is located ortho or meta to a hydroxyl group on thebenzene ring, typically ortho. A “bulky alkyl group” is defined hereinas an alkyl group that is branched alpha- or beta- to the benzene ring.Preferably, the alkyl group is branched alpha to the benzene ring. Morepreferably, the alkyl group is branched twice alpha to the benzene ring,such as in a tert-butyl group. Other examples of bulky alkyl groupsinclude isopropyl, 2-butyl, 3-pentyl, 1,1-dimethylpropyl,1-ethyl-1-methylpropyl and 1,1-diethylpropyl. The bulky alkyl groups arepreferably unsubstituted, but they can be substituted with a functionalgroup that does not interfere with the antioxidant activity of themolecule or the polymer. Straight chained alkoxylcarbonyl groups includemethoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, n-butoxycarbonyl andn-pentoxycarbonyl. n-propoxycarbonyl is a preferred group. Similar tothe bulky alkyl groups, n-alkoxycarbonyl groups are optionallysubstituted with a functional group that does not interfere with theantioxidant activity of the molecule or the polymer.

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention include a polymercomprising repeat units represented by one or both of StructuralFormulas (i) and (ii):

where:

Ring A is substituted with at least one tert-butyl group, and optionallyone or more groups selected from the group consisting of a substitutedor unsubstituted alkyl or aryl group, and a substituted or unsubstitutedalkoxycarbonyl group;

Ring B is substituted with at least one —H and at least one tert-butylgroup and optionally one or more groups selected from the groupconsisting of—a substituted or unsubstituted alkyl or aryl group, and asubstituted or unsubstituted alkoxycarbonyl group;

n is an integer equal to or greater than 2; and

p is an integer equal to or greater than 0.

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention are polymersrepresented by one or both of Structural Formulas (iv) and (v):

where Ring A is substituted with at least one tert-butyl group, andoptionally one or more groups selected from the group consisting of asubstituted or unsubstituted alkyl or aryl group, and a substituted orunsubstituted alkoxycarbonyl group; Ring B is substituted with at leastone —H and at least one tert-butyl group and optionally one or moregroups selected from the group consisting of a substituted orunsubstituted alkyl or aryl group, and a substituted or unsubstitutedalkoxycarbonyl group; R is —H, an optionally substituted C1-C10 alkylgroup, an aryl group, a benzyl group, or an acyl group n is an integerequal to or greater than 2; and p is an integer equal to or greater than0. In one embodiment R is a C1-10 branched or linear alkyl group.

Antioxidant polymers as described immediately above which are suitablefor use in the methods of the present invention have two or more repeatunits, preferably greater than about five repeat units. The molecularweight of the polymers disclosed herein can be generally selected to beappropriate for the desired application. Typically, the molecular weightcan be greater than about 500 atomic mass units (amu) and less thanabout 2,000,000 amu, greater than about 1,000 amu and less than about100,000, greater than about 2,000 amu and less than about 10,000, orgreater than about 2,000 amu and less than about 5,000 amu.

Antioxidant polymers as described immediately above which are suitablefor use in the methods of the present invention can be eitherhomopolymers or copolymers. A copolymer preferably contains two or moreor three or more different repeating monomer units, each of which hasvarying or identical antioxidant properties. The identity of the repeatunits in a copolymer can be chosen to modify the antioxidant propertiesof the polymer as a whole, thereby giving a polymer with tunableproperties. The second, third and/or further repeat units in a copolymercan be either a synthetic or natural antioxidant.

Antioxidant polymers as described immediately above which are suitablefor use in the methods of the present invention are typically insolublein aqueous media. The solubility of the antioxidant polymers innon-aqueous media (e.g., oils) depends upon the molecular weight of thepolymer, such that high molecular weight polymers are typicallysparingly soluble in non-aqueous media. When an antioxidant polymer ofthe invention can be insoluble in a particular medium or substrate, itcan be preferably well-mixed with that medium or substrate.

Antioxidant polymers as described immediately above which are suitablefor use in the methods of the present invention can be branched orlinear, but are preferably linear. Branched antioxidant polymers canonly be formed from benzene molecules having three or fewer substituents(e.g., three or more hydrogen atoms), as in Structural Formulas (XX),(XXI) and (XXIV).

Another specific example of a repeat unit included in polymers which aresuitable for use in the compositions and methods of the presentinvention is represented by the following structural formula:

In another embodiment, the antioxidant polymers which are suitable foruse in the compositions and methods of the present invention includes amacromolecule which can be represented by one or both of StructuralFormulas R and S:

In Structural Formulas R and S, n is an integer equal to or greater than2.

The variable X is O, NH, or S.

The variable Z is H.

Each variable K is independently —H or —OH, with at least one —OHadjacent to a —H; or K is a bond when that position is involved in thepolymer chain.

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention includes amacromolecular antioxidant polymer represented by one or both ofStructural Formulas T and V:

In Structural Formulas T and V, n is an integer equal to or greater than2.

The variable X is O, NH, or S.

The variable Z is H.

Each variable R is independently —H, —OH, a C1-C10 alkyl group, or abond when that position is involved in the polymer chain wherein atleast one —OH is adjacent to a C1-C10 alkyl group, e.g., a tertiarybutyl group.

These macromolecular antioxidant polymers can contain, for example,tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, BHT type repeatunits and their combinations. In some embodiments, of the macromolecularantioxidants described immediately above can be homopolymers,copolymers, terpolymers, and the like

Substituted benzene repeat units of an antioxidant polymer as describedimmediately above which are suitable for use in the methods andcompositions of the present invention are typically substituted with abulky alkyl group or an n-alkoxycarbonyl group. Preferably, the benzenemonomers are substituted with a bulky alkyl group. More preferably, thebulky alkyl group is located ortho or meta to a hydroxyl group on thebenzene ring, typically ortho. A “bulky alkyl group” is defined hereinas an alkyl group that is branched alpha- or beta- to the benzene ring.Preferably, the alkyl group is branched alpha to the benzene ring. Morepreferably, the alkyl group is branched twice alpha to the benzene ring,such as in a tert-butyl group. Other examples of bulky alkyl groupsinclude isopropyl, 2-butyl, 3-pentyl, 1,1-dimethylpropyl,1-ethyl-1-methylpropyl and 1,1-diethylpropyl. The bulky alkyl groups arepreferably unsubstituted, but they can be substituted with a functionalgroup that does not interfere with the antioxidant activity of themolecule or the polymer. Straight chained alkoxylcarbonyl groups includemethoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, n-butoxycarbonyl andn-pentoxycarbonyl. n-propoxycarbonyl is a preferred group. Similar tothe bulky alkyl groups, n-alkoxycarbonyl groups are optionallysubstituted with a functional group that does not interfere with theantioxidant activity of the molecule or the polymer.

Antioxidant polymers as described immediately above which are suitablefor use in the methods and compositions of the present invention havetwo or more repeat units, preferably greater than about five repeatunits. The molecular weight of the polymers disclosed herein can begenerally selected to be appropriate for the desired application.Typically, the molecular weight can be greater than about 500 atomicmass units (amu) and less than about 2,000,000 amu, greater than about1,000 amu and less than about 100,000, greater than about 2,000 amu andless than about 10,000, or greater than about 2,000 amu and less thanabout 5,000 amu.

Antioxidant polymers as described immediately above which are suitablefor use in the methods and compositions of the present invention can beeither homopolymers or copolymers. A copolymer preferably contains twoor more or three or more different repeating monomer units, each ofwhich has varying or identical antioxidant properties. The identity ofthe repeat units in a copolymer can be chosen to modify the antioxidantproperties of the polymer as a whole, thereby giving a polymer withtunable properties. The second, third and/or further repeat units in acopolymer can be either a synthetic or natural antioxidant.

Antioxidant polymers as described immediately above which are suitablefor use in the methods and compositions of the present invention aretypically insoluble in aqueous media. The solubility of the antioxidantpolymers in non-aqueous media (e.g., oils) depends upon the molecularweight of the polymer, such that high molecular weight polymers aretypically sparingly soluble in non-aqueous media. When an antioxidantpolymer of the invention can be insoluble in a particular medium orsubstrate, it can be preferably well-mixed with that medium orsubstrate.

Antioxidant polymers as described immediately above which are suitablefor use in the methods and compositions of the present invention can bebranched or linear, but are preferably linear. Branched antioxidantpolymers can only be formed from benzene molecules having three or fewersubstituents (e.g., three or more hydrogen atoms), as in StructuralFormulas (XX), (XXI) and (XXIV).

Specific examples of repeat units included in polymers which aresuitable for use in the compositions and methods of the presentinvention are represented by one of the following structural formulas:

n is an integer equal to or greater than 2.

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention includes anantioxidant polymer represented by Structural Formula M.

In Structural Formula M:

n is an integer equal to or greater than 2;

R₁ is O, S, or NH;

-   -   R₄, R₅, R₇ and R₈ are independently —H, —OH, —NH, —SH, a        substituted or unsubstituted alkyl or aryl group, or a        substituted or unsubstituted alkoxycarbonyl group, or a bond        when part of the polymer chain,        provided that:

(1) at least one of R₄, R₅, R₇ and R₈ is a tert-butyl group or asubstituted or unsubstituted alkoxycarbonyl group, and at least two ofR₄, R₅, R₇ and R₈ are —H; or

(2) at least one of R₄, R₅, R₇ and R₈ is a tert-butyl group or asubstituted or unsubstituted alkoxycarbonyl group, at least one of R₄,R₅, R₇ and R₈ is a hydroxyl, alkoxy, alkoxycarbonyl or aryloxycarbonylgroup, and at least one of R₄, R₅, R₇ and R₈ is —H.

Substituted benzene repeat units of an antioxidant polymer as describedimmediately above which are suitable for use in the methods andcompositions of the present invention are also typically substitutedwith a bulky alkyl group or an n-alkoxycarbonyl group. Preferably, thebenzene monomers are substituted with a bulky alkyl group. Morepreferably, the bulky alkyl group is located ortho or meta to a hydroxylgroup on the benzene ring, typically ortho. A “bulky alkyl group” isdefined herein as an alkyl group that is branched alpha- or beta- to thebenzene ring. Preferably, the alkyl group is branched alpha to thebenzene ring. More preferably, the alkyl group is branched twice alphato the benzene ring, such as in a tert-butyl group. Other examples ofbulky alkyl groups include isopropyl, 2-butyl, 3-pentyl,1,1-dimethylpropyl, 1-ethyl-1-methylpropyl and 1,1-diethylpropyl. Thebulky alkyl groups are preferably unsubstituted, but they can besubstituted with a functional group that does not interfere with theantioxidant activity of the molecule or the polymer. Straight chainedalkoxylcarbonyl groups include methoxycarbonyl, ethoxycarbonyl,n-propoxycarbonyl, n-butoxycarbonyl and n-pentoxycarbonyl.n-propoxycarbonyl is a preferred group. Similar to the bulky alkylgroups, n-alkoxycarbonyl groups are optionally substituted with afunctional group that does not interfere with the antioxidant activityof the molecule or the polymer.

Antioxidant polymers as described immediately above which are suitablefor use in the methods and compositions of the present invention havetwo or more repeat units, preferably greater than about five repeatunits. The molecular weight of the polymers disclosed herein can begenerally selected to be appropriate for the desired application.Typically, the molecular weight can be greater than about 500 atomicmass units (amu) and less than about 2,000,000 amu, greater than about1,000 amu and less than about 100,000, greater than about 2,000 amu andless than about 10,000, or greater than about 2,000 amu and less thanabout 5,000 amu.

Antioxidant polymers as described immediately above which are suitablefor use in the methods and compositions of the present invention can beeither homopolymers or copolymers. A copolymer preferably contains twoor more or three or more different repeating monomer units, each ofwhich has varying or identical antioxidant properties. The identity ofthe repeat units in a copolymer can be chosen to modify the antioxidantproperties of the polymer as a whole, thereby giving a polymer withtunable properties. The second, third and/or further repeat units in acopolymer can be either a synthetic or natural antioxidant.

Antioxidant polymers as described immediately above which are suitablefor use in the methods and compositions of the present invention aretypically insoluble in aqueous media. The solubility of the antioxidantpolymers in non-aqueous media (e.g., oils) depends upon the molecularweight of the polymer, such that high molecular weight polymers aretypically sparingly soluble in non-aqueous media. When an antioxidantpolymer of the invention can be insoluble in a particular medium orsubstrate, it can be preferably well-mixed with that medium orsubstrate.

Antioxidant polymers as described immediately above which are suitablefor use in the methods and compositions of the present invention can bebranched or linear, but are preferably linear. Branched antioxidantpolymers can only be formed from benzene molecules having three or fewersubstituents (e.g., three or more hydrogen atoms), as in StructuralFormulas (XX), (XXI) and (XXIV).

In another embodiment, antioxidants which are suitable for use in thecompositions and methods of the present invention include a polymerhaving at least one repeat unit that is represented by a structureselected from the group consisting of Structural Formulas (A), (B), (C),(D) and combinations thereof:

R′ is a covalent bond, —O—, —C(O)O—, —C(O)N—, —C(O)—, —CH═CH—, —S— or—N—.

R₁ is —H or an alkyl group, or —(CH₂)_(k)—O—X—Z. Typically, R₁ is —H oralkyl.

Each X is independently a covalent bond, —C(O)—, —C(O)O— or —C(O)N—.

Y is —O—, —N— or —S—.

Each Z is an independently selected antioxidant.

a is an integer from 0 to 12.

Each k is independently an integer from 0 to 12.

m is an integer from 0 to 6.

n is 0 or 1.

p is an integer from 0 to 6.

In one embodiment, the polymer does not include cyclic anhydride repeatunits.

An antioxidant can be attached to the polymer by one or more linkages orbonds. Examples of suitable linkages include acetal, amide, amine,carbamate, carbonate, ester, ether and thioether linkage. Carbon-carbonbonds can be also suitable. As used herein, an amide is distinguishedfrom a diacyl hydrazide.

There are many examples of polymers that can be derivatized with anantioxidant. One type of such polymer has pendant hydroxyl groups, suchas poly(vinyl alcohol) and copolymers thereof (e.g.,poly(ethylene-co-vinyl alcohol)). The hydroxyl groups of poly(vinylalcohol), a polyhydroxyalkyl methacrylate (e.g., polyhydroxy methylmethacrylate), and poly(ethylene-co-vinyl alcohol) react with anantioxidant to form the derivatized antioxidant polymer. Another type ofderivatizable polymer contains pendant carboxylic acid groups or estersthereof, such as poly(acrylic acid), poly(alkylacrylic acid) and estersthereof. Poly(acrylic acid) is a preferred polymer; the carboxylic acidgroups of poly(acrylic acid) can be derivatized, although carboxylicacid groups generally require activation before derivatization canoccur.

An additional type of derivatizable polymer can be a poly(substitutedphenol), where the substituted phenol has a substituent with anucleophilic or electrophilic moiety. Such poly(substituted phenols) caninclude repeat units represented by the following structural formulas:

where a is an integer from 0 to 12; R is —OH, —COOH, —NH₂, —SH or ahalogen; and R₁₀, R₁₁ and R₁₂ are each independently —H, —OH, —NH₂ or—SH, provided that at least one of R₁₀, R₁₁ and R₁₂ is —OH, —NH₂ or —SH.Preferably, one of R₁₀, R₁₁ and R₁₂ is —OH and the remaining two areoptionally —H. More preferably, R₁₁ is —OH and R₁₀ and R₁₂ are —H.

The derivatizable polymers can be homopolymers or copolymers. Copolymersinclude, for example, block, star, hyperbranched, random, gradientblock, and alternate copolymers. The derivatizable polymers can bebranched or linear, but are preferably linear.

In copolymers, it is only necessary for one repeat unit to include apendant reactive group. Second and further repeat units of a copolymercan optionally include a pendant reactive group. For example, about 1%to 100%, such as 10% to 50% or 50% to 100%, of the repeat units of apolymer include pendant functional groups.

All or a fraction of the pendant reactive groups of a derivatizablepolymer can be derivatized with an antioxidant. In one example, about100% of the pendant reactive groups can be derivatized. In anotherexample, about 5% to about 90%, such as about 20% to about 80% (e.g.,about 50% to about 80%) of the pendant reactive groups can bederivatized.

These polymers can be minimally derivatized with a single type ofantioxidant, but can be derivatized with two or more antioxidants (e.g.,chemically distinct antioxidants). When there can be two or moreantioxidants, they can be in the same class, as described below, or canbe in different classes. The ratio of antioxidants can be varied inorder to obtain a polymer having a desired set of properties. Forexample, when a polymer can be derivatized with two antioxidants, theratio of a first antioxidant to a second antioxidant can be from about20:1 to about 1:20, such as from about 5:1 to about 1:5 (e.g., about1:1).

Many antioxidants can be suitable, provided that they can be attached toa polymer and retain their antioxidant activity. One class of suitableantioxidants can be phenolic antioxidants. Phenolic antioxidantstypically have one or more bulky alkyl groups (alkyl groups having asecondary or tertiary carbon alpha to the phenol ring) ortho or meta,preferably ortho, to the phenol hydroxyl group. Phenolic antioxidantscan alternatively have an alkylenedioxy substituent, an alkoxycarbonylsubstituent, a 1-propenyl-3-carboxylic acid substituent or an esterthereof. A preferred bulky alkyl group is a tert-butyl group. The phenolhydroxyl group can be protected by a removable protecting group (e.g.,an acyl group). Phenolic antioxidants for use in the present inventionalso generally have a substituent that can react with the pendantreactive group of one of the polymers described above to form a covalentbond between the antioxidant and the polymer.

One group of suitable phenolic antioxidants can be represented byStructural Formula (E):

R₉ is —H or a substituted or unsubstituted alkyl, acyl or aryl group,preferably —H or an acyl group.

R₄, R₅, R₆, R₇ and R₈ are independently chosen substituent groups, suchthat at least one substituent can be a substituted or unsubstitutedalkyl or aryl group, a substituted or unsubstituted alkoxycarbonylgroup, a substituted or unsubstituted alkylenedioxy group, a1-propenyl-3-carboxylic acid group or an ester thereof. Also, at leastone of R₄, R₅, R₆, R₇ and R₈ must be a substituent capable of reactingwith the pendant reactive group of the polymers described above, such asa substituent having a nucleophilic or electrophilic moiety. Othersuitable substituents include, for example, —H, —OH, —NH and —SH. Asubstituent should not decrease the antioxidant activity more thantwo-fold; instead, substituents preferably increase the antioxidantactivity of the molecule.

Specific examples of phenolic antioxidants that can be attached to apolymer include phenolic antioxidant can be selected from the groupconsisting of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid,3,5-di-tert-butyl-4-hydroxybenzenethiol,2-(3,5-di-tert-butyl-4-hydroxyphenyl)acetic acid,3,5-di-tert-butyl-4-hydroxybenzoic acid,3,5-di-tert-butyl-4-hydroxycinnamic acid, gallic acid, alkyl gallates,3,5-di-tert-butyl-4-hydroxybenzyl alcohol, tert-butyl-hydroquinone,2,5-di-tert-butyl-hydroquinone, 2,6-di-tert-butyl-hydroquinone,3,5-di-tert-butyl-4-hydroxybenzaldehyde,monoacetoxy-tert-butylhydroquinone, sesamol, isoflavones, flavanoids andcoumarins.

Another antioxidant that can be attached to one of the polymersdescribed immediately above can be ascorbic acid or a molecule thatcontains an ascorbic acid moiety. Typically, ascorbic acid attached to apolymer has the following configuration:

where this moiety can be attached to the polymer by an ether or esterlinkage.

Polymers described immediately above which are suitable for use in thecompositions and methods of the present invention can be homopolymers orcopolymers. One type of copolymer includes ethylene repeat units,particularly in a copolymer containing repeat units represented byStructural Formula (A) and/or Structural Formula (B).

In one embodiment of the invention, a polymer comprises repeat unitsrepresented by Structural Formula (A). In a first group of suchpolymers, the sum of m and p is typically two or greater. When the sumof m and p is greater than two, Z is typically a phenolic antioxidant,as described above. One preferred phenolic antioxidant is a3,5-di-tert-butyl-4-hydroxyphenyl group, particularly when X is —C(O)—.For these values of X and Z, m is preferably 2 and n and p are each 0. Asecond preferred antioxidant is a 3,4,5-trihydroxyphenyl group,particularly when X is —C(O)—. Other preferred antioxidants are mono anddi-tert-butylated-4-hydroxyphenyl groups, 4-acetoxy-3-tert-butylphenylgroups and 3-alkoxycarbonyl-2,6-dihydroxyphenyl groups (e.g.,3-propoxycarbonyl-2,6-dihydroxyphenyl groups), particularly when X is acovalent bond.

In a second set of these polymer having repeat units represented byStructural Formula (A), m and p are each 0. When m and p are 0, n isalso typically 0. For these values of m, n and p, Z is typicallyascorbic acid. X is typically a covalent bond. Alternatively, Z is a3,4,5-trihydroxyphenyl group or a 4-acetoxy-3-tert-butylphenyl group,particularly when X is —C(O)—.

In another embodiment of the invention, an antioxidant polymer hasrepeat units represented by Structural Formula (B). For these polymers,m, n and p are each typically 0. Z is preferably a phenolic antioxidant,specifically a 3,4,5-trihydroxyphenyl, 3,5-di-tert-butyl-4-hydroxyphenylgroup or a 3,5-di-1-tert-butyl-2-hydroxyphenyl group.

A further embodiment of the invention involves polymers that includerepeat units represented by Structural Formula (C). In one group of suchpolymers, Y is —O— and Z is preferably ascorbic acid, particularly whenk is 0. In another group, Y is —O— and Z is a phenolic antioxidant,particularly when k is 0 to 3; more preferably, k is 1. A preferredphenolic antioxidant is a 3,5-di-tert-butyl-4-hydroxyphenyl group. Otherexamples include of phenolic antioxidants include4-acetoxy-3-tert-butylphenyl, 3-tert-butyl-4-hydroxyphenyl,2,6-di-tert-butyl-4-mercaptophenyl and 2,6-di-tert-butyl-4-hydroxyphenylgroups.

In yet another embodiment of the invention, a polymer includes repeatunits represented by Structural Formula (D). Typically, R′ is a covalentbond or —OH in such polymers. Other typical values of R′ are amide andester linkages. Preferred Z groups can be phenolic antioxidants, asdescribed above. For these polymers, the phenol hydroxyl group istypically para or meta to the group containing Z, more typically para.

Antioxidant polymers described immediately above which are suitable foruse in the methods of the present invention have two or more repeatunits, preferably greater than about five repeat units. The molecularweight of the polymers disclosed herein can be generally selected to beappropriate for the desired application. Typically, the molecular weightcan be greater than about 500 atomic mass units (amu) and less thanabout 2,000,000 amu, greater than about 1000 amu and less than about1,000,000 amu, greater than about 1000 amu and less than about 100,000amu, greater than about 2,000 amu and less than about 10,000 amu, orgreater than about 2,000 amu and less than about 5,000 amu.

Antioxidant polymers described immediately above which are suitable foruse in the methods of the present invention can be typically insolublein aqueous media. The solubility of the antioxidant polymers innon-aqueous media (e.g., oils) depends upon the molecular weight of thepolymer, such that high molecular weight polymers can be typicallysparingly soluble in non-aqueous media. When an antioxidant polymer ofthe invention can be insoluble in a particular medium or substrate, itcan be preferably well-mixed with that medium or substrate.

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention are represented bythe following structural formula:

n and m in each occurrence, independently is 0 or a positive integer.Preferably 0 to 18 inclusive.

j in each occurrence, independently is 0, 1, 2, 3 or 4.

Z′ in each occurrence, independently is —C(O)O—, —OC(O)—, —C(O)NH—,—NHC(O)—, —NH—, —CH═N—, —N═CH—, —C(O)—, —O—, —S—, —S—S—, —S═N—, —N═S—,—C(S)O—, —OC(S), —OP(O)(OR₄)O—, OP(OR₄)O—, —C(O)OC(O)— or a bond. In oneembodiment, Z′ is —C(O)O—.

R′ in each occurrence, independently is C1-C6 alkyl, —OH, —NH₂, —SH, anoptionally substituted aryl, an optionally substituted ester or

wherein at least one R′ adjacent to the —OH group is an optionallysubstituted bulky alkyl group (e.g., butyl, sec-butyl, tert-butyl,2-propyl, 1,1-dimethylhexyl, and the like).

R′₁, in each occurrence, independently is C1-C6 alkyl, an optionallysubstituted aryl, an optionally substituted aralkyl, —OH, —NH₂, —SH, orC1-C6 alkyl ester wherein at least one R₁ adjacent to the —OH group is abulky alkyl group (e.g., butyl, sec-butyl, tert-butyl, 2-propyl,1,1-dimethylhexyl, and the like).).

M′ is H, an optionally substituted aryl, C1-C20 linear or branched alkylchain with or without any functional group anywhere in the chain,

o is 0 or a positive integer,

R′₂ in each occurrence, independently is —H, C1-C6 alkyl, —OH, —NH₂,—SH, optionally substituted aryl, ester, or

wherein at least one R′₂ is —OH.

R′3 in each occurrence, independently is —H, C1-C6 alkyl, optionallysubstituted aryl, optionally substituted aralkyl —OH, —NH₂, —SH orester.

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention are represented bythe following structural formula:

X′ in each occurrence, independently is —C(O)O—, —OC(O)—, —C(O)NH—,—NHC(O)—, —NH—, —CH═N—, —C(O)—, —O—, —S—, —C(O)OC(O)— or a bond.

R′₂ is C1-C6 alkyl, —OH, —NH₂, —SH, aryl, ester, or

wherein at least one R′₂ is —OH, and the values and preferred values forthe remainder of the variables are as described immediately above.

In certain embodiments Z′ is —C(O)O—. In certain other embodiments Z′ is—OC(O)—. In certain other embodiments Z′ is —C(O)NH—. In certain otherembodiments Z′ is —NHC(O)—. In certain other embodiments Z′ is —NH—. Incertain other embodiments Z′ is —CH═N—. In certain other embodiments Z′is —N═CH—. In certain other embodiments Z′ is —C(O)—. In certain otherembodiments Z′ is —O—. In certain other embodiments Z′ is —S—. Incertain other embodiments Z′ is —S—S—. In certain other embodiments Z′is —S═N—. In certain other embodiments Z′ is —N═S—. In certain otherembodiments Z′ is —C(S)O—. In certain other embodiments Z′ is —OC(S)—.In certain other embodiments Z′ is —OP(O)(OR₄)O—. In certain otherembodiments Z′ is OP(OR₄)O—. In certain other embodiments Z′ is—C(O)OC(O)—. In certain other embodiments Z′ is a bond.

In certain embodiments both R′ groups adjacent to the —OH group is anoptionally substituted bulky alkyl group. In a particular embodimentboth R′ groups adjacent to the —OH group are tert-butyl.

In certain embodiments M′ is

In certain embodiments M′ is

In certain embodiments, at least one R′ is

In certain embodiments n is 0.

In certain embodiments m is 1.

In certain embodiments n is 0, m is 1 and Z is —C(O)O—.

In certain embodiments n is 0, m is 1, Z is —C(O)O— and the two R′groups adjacent to the —OH are t-butyl.

In certain embodiments n is 0, m is 1, Z is —C(O)O—, the two R′ groupsadjacent to the —OH are t-butyl and M′ is

In certain embodiments n is 0, m is 1, Z is —C(O)O—, the two R′ groupsadjacent to the —OH are t-butyl, M′ is

and the R′₂ in the para position is —OH.

In certain embodiments n is 0, m is 1, Z is —C(O)O—, the two R′ groupsadjacent to the —OH are t-butyl, M′ is

the R′₂ in the para position is —OH and an adjacent R′₂ is —OH.

In certain embodiments n is 0, m is 1, Z is —C(O)O—, the two R′ groupsadjacent to the —OH are t-butyl, M′ is

the R′₂ in the para position is —OH and the two adjacent R′₂ are —OH.

In certain embodiments n is 0, m is 1, Z is —C(O)O—, the two R′ groupsadjacent to the —OH are t-butyl, M′ is

In certain embodiments n is 0, m is 1, Z is —C(O)O—, the two R′ groupsadjacent to the —OH are t-butyl, M′ is

and R₃ is —H.

Specific examples of compounds and polymers which are suitable for usein the compositions and methods of the present invention are representedby one of the following structural formulas:

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention include amacromonomer represented by Structural Formula I.

In I, R and R₁-R₆ are independently —H, —OH, or a C1-C10 optionallysubstituted linear or branched alkyl group. n is an integer from 0 to24.

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention include amacromonomer represented by Structural Formula III and an antioxidantpolymer represented by Structural Formula IV. The variables are asdefined above.

Repeat units of the antioxidant polymers as described immediately abovesuitable for use in the compositions and methods of the presentinvention include substituted benzene molecules. These benzene moleculesare typically based on phenol or a phenol derivative, such that theyhave at least one hydroxyl or ether functional group. Preferably, thebenzene molecules have a hydroxyl group. The hydroxyl group can be afree hydroxyl group and can be protected or have a cleavable groupattached to it (e.g., an ester group). Such cleavable groups can bereleased under certain conditions (e.g., changes in pH), with a desiredshelf life or with a time-controlled release (e.g., measured by thehalf-life), which allows one to control where and/or when an antioxidantpolymer can exert its antioxidant effect. The repeat units can alsoinclude analogous thiophenol and aniline derivatives, e.g., where thephenol —OH can be replaced by —SH, —NH—, and the like.

Substituted benzene repeat units of an antioxidant polymer as describedimmediately above suitable for use in the compositions and methods ofthe present invention are also typically substituted with a bulky alkylgroup or an n-alkoxycarbonyl group. Preferably, the benzene monomers aresubstituted with a bulky alkyl group. More preferably, the bulky alkylgroup is located ortho or meta to a hydroxyl group on the benzene ring,typically ortho. A “bulky alkyl group” is defined herein as an alkylgroup that is branched alpha- or beta- to the benzene ring. Preferably,the alkyl group is branched alpha to the benzene ring. More preferably,the alkyl group is branched twice alpha to the benzene ring, such as ina tert-butyl group. Other examples of bulky alkyl groups includeisopropyl, 2-butyl, 3-pentyl, 1,1-dimethylpropyl, 1-ethyl-1-methylpropyland 1,1-diethylpropyl. The bulky alkyl groups are preferablyunsubstituted, but they can be substituted with a functional group thatdoes not interfere with the antioxidant activity of the molecule or thepolymer. Straight chained alkoxylcarbonyl groups includemethoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, n-butoxycarbonyl andn-pentoxycarbonyl. n-propoxycarbonyl is a preferred group. Similar tothe bulky alkyl groups, n-alkoxycarbonyl groups are optionallysubstituted with a functional group that does not interfere with theantioxidant activity of the molecule or the polymer.

Antioxidant polymers as described immediately above suitable for use inthe compositions and methods of the present invention have two or morerepeat units, preferably greater than about five repeat units. Themolecular weight of the polymers disclosed herein can be generallyselected to be appropriate for the desired application. Typically, themolecular weight can be greater than about 500 atomic mass units (amu)and less than about 2,000,000 amu, greater than about 1000 amu and lessthan about 100,000, greater than about 2,000 amu and less than about10,000, or greater than about 2,000 amu and less than about 5,000 amu.

Antioxidant polymers as described immediately above suitable for use inthe compositions and methods of the present invention can be eitherhomopolymers or copolymers. A copolymer preferably contains two or moreor three or more different repeating monomer units, each of which hasvarying or identical antioxidant properties. The identity of the repeatunits in a copolymer can be chosen to modify the antioxidant propertiesof the polymer as a whole, thereby giving a polymer with tunableproperties. The second, third and/or further repeat units in a copolymercan be either a synthetic or natural antioxidant.

Antioxidant polymers as described immediately above suitable for use inthe compositions and methods of the present invention are typicallyinsoluble in aqueous media. The solubility of the antioxidant polymersin non-aqueous media (e.g., oils) depends upon the molecular weight ofthe polymer, such that high molecular weight polymers are typicallysparingly soluble in non-aqueous media. When an antioxidant polymer ofthe invention can be insoluble in a particular medium or substrate, itcan be preferably well-mixed with that medium or substrate.

Antioxidant polymers as described immediately above suitable for use inthe compositions and methods of the present invention can be branched orlinear, but are preferably linear. Branched antioxidant polymers canonly be formed from benzene molecules having three or fewer substituents(e.g., three or more hydrogen atoms).

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention includemacromolecule antioxidants represented by Structural Formula J:

In I, R and R₁-R₆ are independently —H, —OH, or a C1-C10 optionallysubstituted linear or branched alkyl group. n is an integer from 0 to24.

Specific examples of macromolecule antioxidants represented byStructural Formula J which are suitable for use in the compositions andmethods of the present invention are represented by one of the followingstructural formulas:

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention include alkylatedantioxidant macromolecules having formula K:

wherein, independently for each occurrence,

n and m are integers from 0 to 6, inclusive;

Z is —C(O)O—, —OC(O)—, —C(O)NH—, —NHC(O)—, —NH—, —CH═N—, —C(O)—, —O—,—S—, —C(O)OC(O)—, or a bond;

R is H, C₁₋₆ alkyl, —OH, —NH₂, —SH, aryl, aralkyl, or

wherein at least one R adjacent to the —OH group is a bulky alkyl group(e.g., butyl, sec-butyl, tert-butyl, 2-propyl, 1,1-dimethylhexyl, andthe like);

R₁ is H, C₁₋₆ alkyl, aryl, alkylaryl, —OH, —NH₂, —SH, or C1-C6 alkylester wherein at least one R₁ adjacent to the —OH group is a bulky alkylgroup (e.g., butyl, sec-butyl, tert-butyl, 2-propyl, 1,1-dimethylhexyl,and the like); and

R₂ is H, C₁₋₆ alkyl, aryl, aralkyl, —OH, —NH₂, or —SH wherein at leastone R₁ adjacent to the —OH group is a bulky alkyl group (e.g., butyl,sec-butyl, tert-butyl, 2-propyl, 1,1-dimethylhexyl, and the like);

X is —C(O)O—, —OC(O)—, —C(O)NH—, —NHC(O)—, —NH—, —CH═N—, —C(O)—, —O—,—S—, —C(O)OC(O)—, or a bond;

M is H, aryl, C-1 to C-20 linear or branched alkyl chain with or withoutany functional group anywhere in the chain, or

wherein m and each R is independently as described above;

wherein

R₂ is H, C₁₋₆ alkyl, —OH, —NH₂, —SH, aryl, ester, or

wherein at least one R₂ is —OH and n, Z, and each R₁ are independentlyas described above.

In various embodiments, for compounds of formula K, Z is —OC(O)—. Inanother embodiment, Z is —C(O)O—. In another embodiment, Z is —C(O)NH—.In another embodiment, Z is —NHC(O)—. In another embodiment, Z is —NH—.In another embodiment, Z is —CH═N—. In another embodiment, Z is —C(O)—.In another embodiment, Z is —O—. In another embodiment, Z is—C(O)OC(O)—. In another embodiment, Z is a bond.

In another embodiment, for compounds of formula K, both R groupsadjacent to —OH are bulky alkyl groups (e.g., butyl, sec-butyl,tert-butyl, 2-propyl, 1,1-dimethylhexyl, and the like). In anotherembodiment, both R groups are tert-butyl.

In another embodiment, for compounds of formula K, M is

In another embodiment, for compounds of formula K, at least one R is

In another embodiment for compounds of formula K, n is 0.

In another embodiment, for compounds of formula K, m is 1.

In another embodiment, for compounds of formula K, n is 0 and m is 1.

In another embodiment, for compounds of formula K, n is 0, m is 1, and Zis —C(O)O—.

In another embodiment, for compounds of formula K, n is 0, m is 1, Z is—C(O)O—, and the two R groups adjacent to the OH are tert-butyl.

In another embodiment, for compounds of formula K, n is 0, m is 1, Z is—C(O)O—, the two R groups adjacent to the OH are t-butyl, and M is

In another embodiment, for compounds of formula K, n is 0, m is 1, Z is—C(O)O—, the two R groups adjacent to the OH are t-butyl, M is

and the R₂ in the para position is OH.

In another embodiment, for compounds of formula K, n is 0, m is 1, Z is—C(O)O—, the two R groups adjacent to the OH are t-butyl, M is

the R₂ in the para position is OH, and an adjacent R₂ is OH.

In another embodiment, for compounds of formula K, n is 0, m is 1, Z is—C(O)O—, the two R groups adjacent to the OH are t-butyl, M is

the R₂ in the para position is OH, and the two adjacent R₂ groups are—OH.

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention include alkylatedantioxidant macromolecules having formula L.

where M is C1 to C20-linear or branched alkyl chains.

In another embodiment the antioxidants which are suitable for use in thecompositions and methods of the present invention are alkylatedantioxidant macromolecules having formula A:

wherein, independently for each occurrence:

n and m are integers from 0 to 6, inclusive;

Z is —C(O)O—, —OC(O)—, —C(O)NH—, —NHC(O)—, —NH—, —CH═N—, —C(O)—, —O—,—S—, —C(O)OC(O)—, or a bond;

R is H, C₁₋₆ alkyl, —OH, —NH₂, —SH, aryl, ester, or

wherein at least one R adjacent to the —OH group is a bulky alkyl group(e.g., butyl, sec-butyl, tert-butyl, 2-propyl, 1,1-dimethylhexyl, andthe like);

R₁ is H, C₁₋₆ alkyl, aryl, aralkyl, —OH, —NH₂, —SH, or C1-C6 alkyl esterwherein at least one R₁ adjacent to the —OH group is a bulky alkyl group(e.g., butyl, sec-butyl, tert-butyl, 2-propyl, 1,1-dimethylhexyl, andthe like); and

R₂ is H, C₁₋₆ alkyl, aryl, aralkyl, —OH, —NH₂, —SH, or ester, wherein atleast one R₁ adjacent to the —OH group is a bulky alkyl group (e.g.,butyl, sec-butyl, tert-butyl, 2-propyl, 1,1-dimethylhexyl, and thelike);

X is —C(O)O—, —OC(O)—, —C(O)NH—, —NHC(O)—, —NH—, —CH═N—, —C(O)—, —O—,—S—, —C(O)OC(O)—, or a bond;

M is H, aryl, C-1 to C-20 linear or branched alkyl chain with or withoutany functional group anywhere in the chain, or

In one embodiment, the antioxidants which are suitable for use in thecompositions and methods of the present invention are stericallyhindered phenol and phosphite based compounds, represented by a formulaselected from I-III:

Specific examples of compounds which are suitable for use in thecompositions and methods of the present invention are represented by oneof the following structural formulas:

In one embodiment, the antioxidants which are suitable for use in thecompositions and methods of the present invention are stericallyhindered phenol and phosphate based compounds, represented by a formulaselected from O, P and Q.

R is:

R₁ and R₂ in each occurrence, independently is an optionally substitutedalkyl, optionally substituted aryl or optionally substituted aralkyl. Inone embodiment, each R₁ and R₂ are independently an optionallysubstituted alkyl. In another embodiment, each R₁ and R₂ areindependently a linear or branched C1-C6 alkyl.

In one embodiment R is:

In another embodiment R is:

In yet another embodiment R is:

X and Y in each occurrence independently is a bond, —O—, —NH—, —C(O)NH—,—NHC(O)—, —C(O)O—, —OC(O)— or —CH₂—. In one embodiment, X and Y in eachoccurrence independently is a bond or —CH₂—. In another embodiment. Xand Y in each occurrence independently is a bond, —O— or —CH₂—. In yetanother embodiment, X and Y in each occurrence independently is a bond,—NH— or —CH₂—. In yet another embodiment, X and Y in each occurrenceindependently is a bond, —C(O)NH— or —CH₂—. In yet another embodiment, Xand Y in each occurrence independently is a bond, —NHC(O)—, or —CH₂—. Inyet another embodiment, X and Y in each occurrence independently is abond, —C(O)O— or —CH₂—. In yet another embodiment, X and Y in eachoccurrence independently is a bond, —OC(O)— or —CH₂—.

n and m in each occurrence independently is 0 or a positive integer. Inone embodiment, n and m in each occurrence independently is 0 to 18. Inanother embodiment, n and m in each occurrence independently is 0 to 12.In yet another embodiment, n and m are in each occurrence independentlyis 0 to 6.

i and j in each occurrence independently is 0, 1, 2, 3 or 4. In oneembodiment i and j in each occurrence independently is 0, 1 or 2. In aparticular embodiment, i is 0. In another particular embodiment j is 2.

R″ is an optionally substituted alkyl. In one embodiment R″ is C1-C6alkyl.

In a particular embodiment, for compounds represented by structuralformulas O, P and Q, R is:

and n and m in each occurrence independently is 0 to 12, and theremainder of the variables are as described above for structuralformulas O, P and Q.

In another particular embodiment, for compounds represented bystructural formulas O, P and Q, R, n and m are as described immediatelyabove, and R₁ and R₂ in each occurrence, independently is an optionallysubstituted alkyl; i and j in each occurrence independently is 0, 1 or2; and the remainder of the variables are as described above forstructural formulas O, P and Q.

In yet another particular embodiment, for compounds represented bystructural formulas O, P and Q, R₁, R₂, i and j are as describedimmediately above, and R is:

n and m in each occurrence, independently is 0 to 6; and the remainderof the variables are as described above for structural formulas O, P andQ.

In another particular embodiment, for compounds represented bystructural formulas O, P and Q, R₁, R₂, i, j, R, n and m are asdescribed immediately above, and X and Y in each occurrence,independently is a bond or —CH₂—; and the remainder of the variables areas described above for structural formulas O, P and Q.

In another particular embodiment, for compounds represented bystructural formulas O, P and Q, R₁, R₂, i, j, R, n and m are asdescribed immediately above, and X and Y in each occurrence,independently is a bond, —O— or —CH₂—; and the remainder of thevariables are as described above for structural formulas O, P and Q.

In another particular embodiment, for compounds represented bystructural formulas O, P and Q, R₁, R₂, i, j, R, n and m are asdescribed immediately above, and X and Y in each occurrence,independently is a bond, —NH— or —CH₂—; and the remainder of thevariables are as described above for structural formulas O, P and Q.

In another particular embodiment, for compounds represented bystructural formulas O, P and Q, R₁, R₂, i, j, R, n and m are asdescribed immediately above, and X and Y in each occurrence,independently is a bond, —C(O)NH— or —CH₂—; and the remainder of thevariables are as described above for structural formulas O, P and Q.

In another particular embodiment, for compounds represented bystructural formulas O, P and Q, R₁, R₂, i, j, R, n and m are asdescribed immediately above, and X and Y in each occurrence,independently is a bond, —NHC(O)—, or —CH₂—; and the remainder of thevariables are as described above for structural formulas O, P and Q.

In another particular embodiment, for compounds of the present inventionrepresented by structural formulas O, P and Q, R₁, R₂, i, j, R, n and mare as described immediately above, and X and Y in each occurrence,independently is a bond, —C(O)O— or —CH₂—; and the remainder of thevariables are as described above for structural formulas O, P and Q.

In another particular embodiment, for compounds of the present inventionrepresented by structural formulas O, P and Q, R₁, R₂, i, j, R, n and mare as described immediately above, and X and Y in each occurrence,independently is a bond, —OC(O)— or —CH₂—; and the remainder of thevariables are as described above for structural formulas O, P and Q.

In an additional embodiment, for formulas O, P and Q R is:

n and m in each occurrence, independently is 0 or a positive integer. Inone embodiment, n and m in each occurrence, independently is 0 to 18. Inanother embodiment, n and m in each occurrence, independently is 0 to12. In yet another embodiment, n and m in each occurrence, independentlyis 0 to 6.

i and j in each occurrence, independently is 0, 1, 2, 3 or 4. In oneembodiment, i and j in each occurrence, independently is 0, 1 or 2. In aparticular embodiment, i is 0. In another particular embodiment, j is 2.

Z′ is —C(O)O—, —OC(O)—, —C(O)NH—, —NHC(O)—, —NH—, —CH═N—, —C(O)—, —O—,—S—, —C(O)OC(O)— or a bond. In one embodiment, Z′ is —C(O)O—. In anotherembodiment, Z′ is —OC(O)—. In yet another embodiment, Z′ is —C(O)NH—. Inyet another embodiment, Z′ is —NHC(O)—. In yet another embodiment, Z′ is—NH—. In yet another embodiment, Z′ is —CH═N—. In yet anotherembodiment, Z′ is —C(O)—. In yet another embodiment, Z′ is —O—. In yetanother embodiment, Z′ is —S—. In yet another embodiment, Z′ is—C(O)OC(O)—. In yet another embodiment, Z′ is a bond.

R′ is an optionally substituted C1-C6 alkyl, —OH, —NH₂, —SH, anoptionally substituted aryl, an ester or

wherein at least one R′ adjacent to the —OH group is an optionallysubstituted bulky alkyl group (e.g., butyl, sec-butyl, tert-butyl,2-propyl, 1,1-dimethylhexyl, and the like).

R′₁, is an optionally substituted C1-C6 alkyl, an optionally substitutedaryl, an optionally substituted aralkyl, —OH, —NH₂, —SH, or C1-C6 alkylester wherein at least one R₁ adjacent to the —OH group is a bulky alkylgroup (e.g., butyl, sec-butyl, tert-butyl, 2-propyl, 1,1-dimethylhexyl,and the like).).

R′₂ is an optionally substituted C1-C6 alkyl, an optionally substitutedaryl, an optionally substituted aralkyl, —OH, —NH₂, —SH, or ester.

X′ is —C(O)O—, —OC(O)—, —C(O)NH—, —NHC(O)—, —NH—, —CH═N—, —C(O)—, —O—,—S—, —C(O)OC(O)— or a bond. In one embodiment X′ is —C(O)O—. In anotherembodiment X′ is —OC(O)—. In yet another embodiment X′ is —C(O)NH—. Inyet another embodiment X′ is —NHC(O)—. In yet another embodiment X′ is—NH—. In yet another embodiment X′ is —CH═N—. In yet another embodimentX′ is —C(O)—. In yet another embodiment X′ is —O—. In yet anotherembodiment X′ is —S—. In yet another embodiment X′ is —C(O)OC(O)—. Inyet another embodiment X′ is a bond.

M′ is H, an optionally substituted aryl, an optionally substitutedC1-C20 linear or branched alkyl chain with or without any functionalgroup anywhere in the chain, or

o is 0 or a positive integer. Preferably o is 0 to 18. More preferably ois 0 to 12. Even more preferably o is 0 to 6.

In yet another embodiment, for formulas O, P and Q R is:

R′₂ is C1-C6 alkyl, —OH, —NH₂, —SH, aryl, ester, aralkyl or

wherein at least one R′₂ is —OH, and the values and preferred values forthe remainder of the variables for R are as described immediately above.

In yet another embodiment, the present invention relates to a compoundof formula O, P and Q, wherein M is

Wherein p is 0, 1, 2, 3 or 4; and the values and preferred values forthe remainder of the variables are as described above for formulas O, Pand Q.

Specific examples of compounds which are suitable for use in thecompositions and methods of the present invention are represented by oneof the following structural formulas:

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention are represented bya structural formula selected from 1-6:

R is:

A in each occurrence, independently is a bond, —O—, —NH—, —S—, —C(O)—,—C(O)NH—, —NHC(O)—, —C(O)O—, —OC(O)—, —CH═N— or —N═CH—. In certainparticular embodiments, A in each occurrence, independently is —C(O)NH—or —NHC(O)—.

B in each occurrence, independently is a bond or an optionallysubstituted alkylene group. In certain particular embodiments B is aC1-C6 alkyl.

C in each occurrence, independently is —H, an optionally substitutedalkyl group or

In a particular embodiment, C is:

In a particular embodiment R is:

In another particular embodiment R is:

In yet another particular embodiment R is:

R₁ and R₂ in each occurrence, independently is an optionally substitutedalkyl, optionally substituted aryl or optionally substituted aralkyl. Inone embodiment, each R₁ and R₂ in each occurrence, independently is anoptionally substituted alkyl. In another embodiment, each R₁ and R₂ ineach occurrence, independently is a C1-C6 alkyl.

D in each occurrence, independently is a bond, an optionally substitutedalkylene group, —(CH₂)₁C(O)O(CH₂)₁—, —(CH₂)₁NHC(O)(CH₂)₁—,—(CH₂)₁C(O)NH(CH₂)₁—, —(CH₂)₁C(O)O(CH₂)₁—, —(CH₂)₁OC(O)(CH₂)₁—,—(CH₂)₁CH═N(CH₂)₁—, —(CH₂)₁N═CH(CH₂)₁—, —(CH₂)₁NH(CH₂)₁—,—(CH₂)₁S—(CH₂)₁—, —(CH₂)₁—O—(CH₂)₁— or —(CH₂)₁C(O)(CH₂)₁—.

Z in each occurrence, independently is a bond, an optionally substitutedalkylene group, —S—, —O— or —NH—.

i and j in each occurrence, independently is 0, 1, 2, 3 or 4. In oneembodiment i and j in each occurrence, independently is 0, 1 or 2. In aparticular embodiment, i is 0. In another particular embodiment, j is 2.

k is a positive integer from 1 to 20. In one embodiment, k is a positiveinteger from 1 to 12. In another embodiment, k is a positive integerfrom 1 to 6.

1 is 0 or a positive integer from 1 to 20. In one embodiment, 1 is 0 ora positive integer from 1 to 12. In another embodiment, 1 is 0 or apositive integer from 1 to 6.

n and m in each occurrence independently is 0 or a positive integer. Inone embodiment, n and m in each occurrence independently is 0 to 18. Inanother embodiment, n and m in each occurrence independently is 0 to 12.In yet another embodiment, n and m are in each occurrence independentlyis 0 to 6.

s is a positive integer from 1 to 6.

q is a positive integer from 1 to 3.

In certain other embodiments R is:

R₁ and R₂ in each occurrence, independently is —H, —OH, a C1-C10 alkylgroup or a tert-butyl group; A is —NHC(O)— or —C(O)O— and B is a bond ora C1-C24 alkylene, and i and j are 0, 1, 2, 3 or 4.

In an additional embodiment, for formulas 1-6 R is:

n and m in each occurrence, independently is 0 or a positive integer. Inone embodiment, n and m in each occurrence, independently is 0 to 18. Inanother embodiment, n and m in each occurrence, independently is 0 to12. In yet another embodiment, n and m in each occurrence, independentlyis 0 to 6.

i and j in each occurrence, independently is 0, 1, 2, 3 or 4. In oneembodiment, i and j in each occurrence, independently is 0, 1 or 2. In aparticular embodiment, i is 0. In another particular embodiment, j is 2.

Z′ in each occurrence, independently is —C(O)O—, —OC(O)—, —C(O)NH—,—NHC(O)—, —NH—, —CH═N—, —C(O)—, —O—, —S—, —C(O)OC(O)— or a bond. In oneembodiment, Z′ is —C(O)O—. In another embodiment, Z′ is —OC(O)—. In yetanother embodiment, Z′ is —C(O)NH—. In yet another embodiment, Z′ is—NHC(O)—. In yet another embodiment, Z′ is —NH—. In yet anotherembodiment, Z′ is —CH═N—. In yet another embodiment, Z′ is —C(O)—. Inyet another embodiment, Z′ is —O—. In yet another embodiment, Z′ is —S—.In yet another embodiment, Z′ is —C(O)OC(O)—. In yet another embodiment,Z′ is a bond.

R′ in each occurrence, independently is C1-C6 alkyl, —OH, —NH₂, —SH, anoptionally substituted aryl, an ester or

wherein at least one R′ adjacent to the —OH group is an optionallysubstituted bulky alkyl group (e.g., butyl, sec-butyl, tert-butyl,2-propyl, 1,1-dimethylhexyl, and the like).

R′₁ in each occurrence, independently is C1-C6 alkyl, an optionallysubstituted aryl, an optionally substituted aralkyl, —OH, —NH₂, —SH, orC1-C6 alkyl ester wherein at least one R₁ adjacent to the —OH group is abulky alkyl group (e.g., butyl, sec-butyl, tert-butyl, 2-propyl,1,1-dimethylhexyl, and the like).).

R′₂ in each occurrence, independently is C1-C6 alkyl, an optionallysubstituted aryl, an optionally substituted aralkyl, —OH, —NH₂, —SH, orester.

X′ in each occurrence, independently is —C(O)O—, —OC(O)—, —C(O)NH—,—NHC(O)—, —NH—, —CH═N—, —C(O)—, —O—, —S—, —C(O)OC(O)— or a bond. In oneembodiment X′ is —C(O)O—. In another embodiment X′ is —OC(O)—. In yetanother embodiment X′ is —C(O)NH—. In yet another embodiment X′ is—NHC(O)—. In yet another embodiment X′ is —NH—. In yet anotherembodiment X′ is —CH═N—. In yet another embodiment X′ is —C(O)—. In yetanother embodiment X′ is —O—. In yet another embodiment X′ is —S—. Inyet another embodiment X′ is —C(O)OC(O)—. In yet another embodiment X′is a bond.

M′ is H, an optionally substituted aryl, C1-C20 linear or branched alkylchain with or without any functional group anywhere in the chain, or

o is 0 or a positive integer. Preferably o is 0 to 18. More preferably ois 0 to 12. Even more preferably o is 0 to 6.

In yet another embodiment, for formulas 1-6 R is:

R′₂ is C1-C6 alkyl, —OH, —NH₂, —SH, aryl, aralkyl, ester, or

wherein at least one R′₂ is —OH, and the values and preferred values forthe remainder of the variables for R are as described immediately above.

In yet another embodiment, the present invention relates to a compoundof formula 1-6, wherein M is

Wherein p is 0, 1, 2, 3 or 4; and the values and preferred values forthe remainder of the variables are as described above for formulas 1-6.

Specific examples of macromolecular antioxidants which are suitable foruse in the compositions and methods of the present invention, forexample, high molecular weight dimers, and tetramers etc., are shownbelow.

The values and preferred values for the variables are as describedabove.

In another embodiment, the antioxidants which are suitable for use inthe compositions and methods of the present invention are represented bya structural formula selected from 7a, 7b, 8a and 8b:

R₃ and R₄ in each occurrence, independently is C1-C16 alkyl, —O—(C1-C16alkyl), —NH(aryl), —NH₂, —OH, or —SH.

p in each occurrence, independently is an integer equal to or greaterthan 2.

Specific examples of polymers which are useful in the compositionsmethods of the present invention include:

In one embodiment, of the present invention the compositions for use instabilization of polyolefins, include but are not limited to:

a. an antioxidant (in the concentration range, from about 0.0001% toabout 50%, from about 0.0005% to about 20%, from about 0.005% to about10%, from about 0.05% to about 5% or from about 0.01% to about 1%) withacid scavengers, for example, in amounts of from about 0.0005% to about50%, from about 0.0001% to about 20%, from about 0.005% to about 10%,from about 0.05% to about 5% or from about 0.01% to about 1% by weight,based on the weight of polyolefin to be stabilized.

b. an antioxidant (in the concentration range from about 0.0005% toabout 50%, from about 0.0001% to about 20%, from about 0.005% to about10%, from about 0.05% to about 5% or from about 0.01% to about 1%) alongwith organic phosphorus stabilizers. The organic phosphorus stabilizersare used for example, in amounts of, from about 0.001% to about 30%,from about 0.005% to about 20%, from about 0.01% to about 5%, from about0.05% to about 2% or from about 0.1% to about 1%, by weight, based onthe weight of the polyolefin to be stabilized.

c. an antioxidant (in the concentration range from about 0.0005% toabout 50%, from about 0.0001% to about 50%, from about 0.005% to about10%, from about 0.05% to about 5% or from about 0.01% to about 1%) alongwith acid scavengers and organic phosphorus stabilizers inconcentrations described in a. and b. above.

d. an antioxidant in combination with other known commercially availableantioxidants, such as, for example, Irganox® 1010, Irganox® 1330,Irganox® 1076 and Irganox® 1135 or other antioxidants described above orincorporated herein by reference along with the formulations describedin a.-c. above.

Polyolefins

In certain embodiments of the present invention, polyolefins andmixtures of polyolefins can be stabilized by contacting the polyolefinor mixture of polyolefins with a composition of the present invention.These polyolefins and mixtures of polyolefins, include, but are notlimited to substituted polyolefins, polyacrylates, polymethacrylates andcopolymers of polyolefins. The following are examples of some types ofpolyolefins which can be stabilized by the methods of the presentinvention:

1. Polymers of monoolefins and diolefins, for example polypropylene,polyisobutylene, polybut-1-ene, poly-4-methylpent-1-ene, polyisoprene orpolybutadiene, as well as polymers of cycloolefins, for instance ofcyclopentene or norbornene, polyethylene (which optionally can becrosslinked), for example high density polyethylene (HDPE), high densityand high molecular weight polyethylene (HDPE-HMW), high density andultrahigh molecular weight polyethylene (HDPE-UHMW), medium densitypolyethylene (MDPE), low density polyethylene (LDPE), linear low densitypolyethylene (LLDPE), very low density polyethylene (VLDPE) and ultralow density polyethylene (ULDPE).

Polyolefins, i.e. the polymers of monoolefins exemplified in thepreceding paragraph, for example polyethylene and polypropylene, can beprepared by different, and especially by the following, methods:

i) radical polymerization (normally under high pressure and at elevatedtemperature).

ii) catalytic polymerization using a catalyst that normally contains oneor more than one metal of groups IVb, Vb, VIb or VIII of the PeriodicTable. These metals usually have one or more than one ligand, typicallyoxides, halides, alcoholates, esters, ethers, amines, alkyls, alkenylsand/or aryls that may be either p- or s-coordinated. These metalcomplexes may be in the free form or fixed on substrates, typically onactivated magnesium chloride, titanium(III) chloride, alumina or siliconoxide. These catalysts may be soluble or insoluble in the polymerizationmedium. The catalysts can be used by themselves in the polymerization orfurther activators may be used, typically metal alkyls, metal hydrides,metal alkyl halides, metal alkyl oxides or metal alkyloxanes, saidmetals being elements of groups Ia, IIa and/or IIIa of the PeriodicTable. The activators may be modified conveniently with further ester,ether, amine or silyl ether groups. These catalyst systems are usuallytermed Phillips, Standard Oil Indiana, Ziegler (-Natta), TNZ (DuPont),metallocene or single site catalysts (SSC).

2. Mixtures of the polymers mentioned under 1, for example, mixtures ofpolypropylene with polyisobutylene, polypropylene with polyethylene (forexample PP/HDPE, PP/LDPE) and mixtures of different types ofpolyethylene (for example LDPE/HDPE).

3. Copolymers of monoolefins and diolefins with each other or with othervinyl monomers, for example ethylene/propylene copolymers, linear lowdensity polyethylene (LLDPE) and mixtures thereof with low densitypolyethylene (LDPE), propylene/but-1-ene copolymers,propylene/isobutylene copolymers, ethylene/but-1-ene copolymers,ethylene/hexene copolymers, ethylene/methylpentene copolymers,ethylene/heptene copolymers, ethylene/octene copolymers,propylene/butadiene copolymers, isobutylene/isoprene copolymers,ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylatecopolymers, ethylene/vinyl acetate copolymers and their copolymers withcarbon monoxide or ethylene/acrylic acid copolymers and their salts(ionomers) as well as terpolymers of ethylene with propylene and a dienesuch as hexadiene, dicyclopentadiene or ethylidene-norbornene; andmixtures of such copolymers with one another and with polymers mentionedin 1) above, for example polypropylene/ethylene-propylene copolymers,LDPE/ethylene-vinyl acetate copolymers (EVA), LDPE/ethylene-acrylic acidcopolymers (EAA), LLDPE/EVA, LLDPE/EAA and alternating or randompolyalkylene/carbon monoxide copolymers and mixtures thereof with otherpolymers, for example polyamides.

4. Blends of polymers mentioned under 1. with impact modifiers such asethylene-propylene-diene monomer copolymers (EPDM), copolymers ofethylene with higher alpha-olefins (such as ethylene-octene copolymers),polybutadiene, polyisoprene, styrene-butadiene copolymers, hydrogenatedstyrene-butadiene copolymers, styrene-isoprene copolymers, hydrogenatedstyrene-isoprene copolymers. These blends are commonly referred to inthe industry as TPO's (thermoplastic polyolefins).

In certain particular embodiments polyolefins of the present inventionare for example polypropylene homo- and copolymers and polyethylenehomo- and copolymers. For instance, polypropylene, high densitypolyethylene (HDPE), linear low density polyethylene (LLDPE) andpolypropylene random and impact (heterophasic) copolymers.

Stabilizers

Acid Scavengers or Acid Stabilizers

“Acid scavengers or stabilizers” are defined herein as antacids orco-stabilizers which neutralize the acidic catalysts or other componentspresent in the polymers.

In certain embodiments, of the present invention the acid scavengerswhich are suitable for use in the methods of the present inventioninclude but are not limited to: zinc oxide, calcium lactate, natural andsynthetic hydrotalcites, natural and synthetic hydrocalumites, andalkali metal salts and alkaline earth metal salts of higher fatty acidsfor example calcium stearate, zinc stearate, magnesium behenate,magnesium stearate, sodium stearate, sodium ricinoleate and potassiumpalmitate, antimony pyrocatecholate and zinc pyrocatecholate.Combinations of acid scavengers may also be employed.

In certain particular embodiments, the acid scavengers are used forexample, in amounts of from about 0.0005% to about 50% by weight, about0.0001% to about 20% by weight, about 0.005% to about 5% by weight,about 0.01% to about 3% by weight, about 0.05% to about 2% by weight, orabout 0.1% to about 1% by weight, based on the weight of polyolefin tobe stabilized.

Organic Phosphorus Stabilizers

In certain embodiments of the present invention, examples of organicphosphorus stabilizers (or phosphorus stabilizers) include phosphates,phosphites and phosphonites which are suitable for use in the methods ofthe present invention. Specific examples of phosphorus stabilizersinclude but are not limited to: triphenyl phosphite, diphenyl alkylphosphites, phenyl dialkyl phosphites, tris(nonylphenyl) phosphite,trilauryl phosphite, trioctadecyl phosphite, distearyl pentaerythritoldiphosphite, tris(2,4-di-tert-butylphenyl)phosphite, ethanamine,2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,2,3]dioxaphosphepin-6-yl]oxy]-N,N-[bis[2-[[2,4,8,10-tetrakis(1,1dimethylethyl)dibenzo[d,f][1,2,3]dioxaphepin-6-yl]oxy]ethyl](represented by structural formula (B) diisodecyl pentaerythritoldiphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite(represented by structural formula (D) below),bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite(represented by structural formula (E) below),3,9-bis(octadecylpxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5undecane(represented by structural formula (F), bisisodecyloxy-pentaerythritoldiphosphite, bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritoldiphosphite, bis(2,4,6-tri-tert-butylphenyl)pentaerythritol diphosphite,tristearyl sorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl)4,4′-biphenylene-diphosphonite (represented by structural formula (H)below),6-isooctyloxy-2,4,8,10-tetra-tert-butyl-dibenzo[d,f][1,3,2]dioxaphosphepin(represented by structural formula (C) below),6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenzo[d,g][1,3,2]dioxaphosphocin(represented by structural formula (A) below),bis(2,4-di-tert-butyl-6-methylphenyl)methyl phosphite,bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite (represented bystructural formula (G) below), (2,4,6-tri-tert-butylphenyl)2-butyl-2-ethyl-1,3-propanediol phosphate (represented by structuralformula (J) below), bis(2,4-di-cumylphenyl)pentaerythritol diphosphite(represented by structural formula (K) below), and structural formula(L) below:

In certain other embodiments of the present invention, the followingcompounds are examples of organic phosphites and phosphonites which aresuitable for use in the methods of the present invention as organicphosphorus stabilizers: tris(2,4-di-tert-butylphenyl) phosphite,bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite (formula (D)),tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylene-diphosphonite(formula (H)),(2,4,6-tri-tert-butylphenyl)2-butyl-2-ethyl-1,3-propanediol phosphate(formula (J)), or bis(2,4-di-cumylphenyl)pentaerythritol diphosphite(formula (K)).

The organic phosphorus stabilizers are used, for example, in amounts offrom about 0.001% to about 50% by weight, about 0.005% to about 20% byweight, about 0.01% to about 5% by weight, 0.05% to about 3% by weight,0.1% to about 2% by weight or 0.1% to about 1% by weight based on theweight of the polyolefin to be stabilized.

Co-Stabilizers

In certain embodiments of the present invention, in addition toantioxidants and stabilizers described above the compositions of thepresent invention may comprise further co-stabilizers (e.g., additives)such as, for example, the following:

1. Antioxidants

1.1. Alkylated monophenols, for example2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol,2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol,2,6-di-tert-butyl-4-isobutylphenol, 2,6-di-tert-butyl-4-octadecylphenol,2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,2,6-di-tert-butyl-4-methoxymethylphenol, nonylphenols which are linearor branched in the side chains, for example,2,6-di-nonyl-4-methylphenol,2,4-dimethyl-6-(1′-methylundec-1′-yl)phenol,2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol,2,4-dimethyl-6-(1′-methyltridec-1′-yl)phenol and mixtures thereof.

1.2. Alkylthiomethylphenols, for example2,4-dioctylthiomethyl-6-tert-butylphenol,2,4-dioctylthiomethyl-6-methylphenol,2,4-dioctylthiomethyl-6-ethylphenol,2,6-di-dodecylthiomethyl-4-nonylphenol.

1.3. Hydroquinones and alkylated hydroquinones, for example2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octadecyloxyphenol,2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenylstearate, bis-(3,5-di-tert-butyl-4-hydroxyphenyl)adipate.

1.4. Tocopherols, for example α-tocopherol, β-tocopherol, γ-tocopherol,δ-tocopherol and mixtures thereof (Vitamin E).

1.5. Hydroxylated thiodiphenyl ethers, for example2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol),4,4′-thiobis(6-tert-butyl-3-methylphenol),4,4′-thiobis(6-tert-butyl-2-methylphenol),4,4′-thiobis-(3,6-di-sec-amylphenol),4,4′-bis(2,6-dimethyl-4-hydroxyphenyl)disulfide.

1.6. Alkylidenebisphenols, for example 2,2′-methylenebis(6-tert-butyl-4-methylphenol),2,2′-methylenebis(6-tert-butyl-4-ethylphenol),2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol],2,2′-methylenebis(4-methyl-6-cyclohexylphenol),2,2′-methylenebis(6-nonyl-4-methylphenol),2,2′-methylenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2′-methylenebis[6-(α-methylbenzyl)-4-nonylphenol],2,2′-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol],4,4′-methylenebis(2,6-di-tert-butylphenol),4,4′-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane,ethylene glycol bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene,bis[2-(3′-tert-butyl-2′-hydroxy-5′-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate,1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane,2,2-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propane,2,2-bis-(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane,1,1,5,5-tetra-(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane.

1.7. O-, N- and S-benzyl compounds, for example3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxydibenzyl ether,octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate,tridecyl-4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate,tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine,bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate,bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide,isooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate.

1.8. Hydroxybenzylated malonates, for exampledioctadecyl-2,2-bis-(3,5-di-tert-butyl-2-hydroxybenzyl)malonate,di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)malonate,di-dodecylmercaptoethyl-2,2-bis-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate,bis[4-(1,1,3,3-tetramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.

1.9. Aromatic hydroxybenzyl compounds, for example 1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene,2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.

1.10. Triazine compounds, for example2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine,1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)-hexahydro-1,3,5-triazine,1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate.

1.11. Benzylphosphonates, for example dimethyl2,5-di-tert-butyl-4-hydroxybenzylphosphonate, diethyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate, the calcium salt ofthe monoethyl ester of 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid.

1.12. Acylaminophenols, for example 4-hydroxylauranilide,4-hydroxystearanilide, octylN-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.

1.13. Esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid withmono- or polyhydric alcohols, e.g. with methanol, ethanol, n-octanol,i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.14. Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acidwith mono- or polyhydric alcohols, e.g. with methanol, ethanol,n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol,ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethyleneglycol, diethylene glycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.15. Esters of β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid withmono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.16. Esters of 3,5-di-tert-butyl-4-hydroxyphenyl acetic acid with mono-or polyhydric alcohols, e.g. with methanol, ethanol, octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.17. Amides of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid,e.g.N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamide,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamide,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazide,N,N′-bis[2-(3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyloxy)ethyl]oxamide(Naugard® XL-1, Crompton Corporation).

1.18. Ascorbic acid (vitamin C)

1.19. Aminic antioxidants, for exampleN,N′-di-isopropyl-p-phenylenediamine,N,N′-di-sec-butyl-p-phenylenediamine,N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine,N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine,N,N′-bis(1-methylheptyl)-p-phenylenediamine,N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine,N,N′-bis(2-naphthyl)-p-phenylenediamine,N-isopropyl-N′-phenyl-p-phenylenediamine,N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine,N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine,N-cyclohexyl-N′-phenyl-p-phenylenediamine,4-(p-toluenesulfamoyl)diphenylamine,N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine,N-allyldiphenylamine, 4-isopropoxydiphenylamine,N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine,N-phenyl-2-naphthylamine, octylated diphenylamine, for examplep,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol,4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol,4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine,2,6-di-tert-butyl-4-dimethylaminomethylphenol,2,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,N,N,N′,N′-tetramethyl-4,4′-diaminodiphenylmethane,1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane,(o-tolyl)biguanide, bis[4-(1′,3′-dimethylbutyl)phenyl]amine,tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- anddialkylated tert-butyl/tert-octyldiphenylamines, a mixture of mono- anddialkylated nonyldiphenylamines, a mixture of mono- and dialkylateddodecyldiphenylamines, a mixture of mono- and dialkylatedisopropyl/isohexyldiphenylamines, a mixture of mono- and dialkylatedtert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine,phenothiazine, a mixture of mono- and dialkylatedtert-butyl/tert-octylphenothiazines, a mixture of mono- and dialkylatedtert-octylphenothiazines, N-allylphenothiazin,N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene,N,N-bis(2,2,6,6-tetramethyl-piperid-4-yl-hexamethylenediamine,bis(2,2,6,6-tetramethylpiperid-4-yl)sebacate,2,2,6,6-tetramethylpiperidin-4-one, 2,2,6,6-tetramethylpiperidin-4-ol.

2. Hindered Amine Stabilizers

As defined herein, “hindered amine stabilizers” are hindered amineswhich produce nitroxyl radicals that react with alkyl radicals producedduring thermo-oxidation of the polymers.

2.1. Sterically hindered amine stabilizers, for example4-hydroxy-2,2,6,6-tetramethylpiperidine,1-allyl-4-hydroxy-2,2,6,6-tetramethylpiperidine,1-benzyl-4-hydroxy-2,2,6,6-tetramethylpiperidine,bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis(2,2,6,6-tetramethyl-4-piperidyl)succinate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinicacid, linear or cyclic condensates ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-triazine,tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate,tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane-tetracarboxylate,1,1′-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyloxy-2,2,6,6-tetramethylpiperidine,bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate,3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decan-2,4-dione,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate, linear or cycliccondensates ofN,N′-bis-(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-morpholino-2,6-dichloro-1,3,5-triazine, the condensate of2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane, the condensate of2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazineand 1,2-bis-(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidin-2,5-dione,3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione, amixture of 4-hexadecyloxy- and4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensation product ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, a condensation product of1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine aswell as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No.[136504-96-6]); N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsuccinimid,N-(1,2,2,6,6-pentamethyl-4-piperidyl)-n-dodecylsuccinimid,2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4,5]decane, areaction product of7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro[4,5]decaneand epichlorohydrin,1,1-bis-(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)-2-(4-methoxyphenyl)ethene,N,N′-bis-formyl-N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine,diester of 4-methoxy-methylene-malonic acid with1,2,2,6,6-pentamethyl-4-hydroxypiperidine,poly[methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-piperidyl)]siloxane,reaction product of maleic acid anhydride-α-olefin-copolymer with2,2,6,6-tetramethyl-4-aminopiperidine or1,2,2,6,6-pentamethyl-4-aminopiperidine.

The sterically hindered amine may also be one of the compounds describedin U.S. Pat. No. 5,980,783, the entire contents of which areincorporated herein by reference, that is compounds of component I-a),I-b), I-c), I-d), I-e), I-f), I-g), I-h), I-i), I-j), I-k) or I-l), inparticular the light stabilizer 1-a-1, 1-a-2, 1-b-1, 1-c-1, 1-c-2,1-d-1, 1-d-2, 1-d-3, 1-e-1, 1-f-1, 1-g-1, 1-g-2 or 1-k-1 listed oncolumns 64-72 of said U.S. Pat. No. 5,980,783.

The sterically hindered amine may also be one of the compounds describedin U.S. Pat. Nos. 6,046,304 and 6,297,299, the entire contents of eachof which are incorporated herein by reference, for example compounds asdescribed in claim 10 or 38 or in Examples 1-12 or D-1 to D-5 therein.

2.2. Sterically hindered amines substituted on the N-atom by ahydroxy-substituted alkoxy group, for example compounds such as1-(2-hydroxy-2-methylpropoxy)-4-octadecanoyloxy-2,2,6,6-tetramethylpiperidine,1-(2-hydroxy-2-methylpropoxy)-4-hexadecanoyloxy-2,2,6,6-tetramethylpiperidine,the reaction product of 1-oxy]-4-hydroxy-2,2,6,6-tetramethylpiperidinewith a carbon radical from t-amylalcohol,1-(2-hydroxy-2-methylpropoxy)-4-hydroxy-2,2,6,6-tetramethylpiperidine,1-(2-hydroxy-2-methylpropoxy)-4-oxo-2,2,6,6-tetramethylpiperidine,bis(1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,bis(1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl)adipate,bis(1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl)succinate,bis(1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl)glutarateand2,4-bis{N-[1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl]-N-butylamino}-6-(2-hydroxyethylamino)-s-triazine.

3. Ultraviolet Absorbers

As defined herein “ultraviolet absorbers” essentially absorb the harmfulUV radiation and dissipate it so that is does not lead tophotosensitization i.e., dissipation as heat.

3.1. 2-(2-Hydroxyphenyl)-2H-benzotriazoles, for example known commercialhydroxyphenyl-2H-benzotriazoles and benzotriazoles as disclosed in, U.S.Pat. Nos. 3,004,896; 3,055,896; 3,072,585; 3,074,910; 3,189,615;3,218,332; 3,230,194; 4,127,586; 4,226,763; 4,275,004; 4,278,589;4,315,848; 4,347,180; 4,383,863; 4,675,352; 4,681,905, 4,853,471;5,268,450; 5,278,314; 5,280,124; 5,319,091; 5,410,071; 5,436,349;5,516,914; 5,554,760; 5,563,242; 5,574,166; 5,607,987 and 5,977,219, theentire contents of each of which are incorporated herein by reference,such as 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole,2-(3,5-di-tert-butyl-2-hydroxyphenyl)-2H-benzotriazole,2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole,2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole,5-chloro-2-(3,5-di-tert-butyl-2-hydroxyphenyl)-2H-benzotriazole,5-chloro-2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-2H-benzotriazole,2-(3-sec-butyl-5-tert-butyl-2-hydroxyphenyl)-2H-benzotriazole,2-(2-hydroxy-4-octyloxyphenyl)-2H-benzotriazole,2-(3,5-di-tert-amyl-2-hydroxyphenyl)-2H-benzotriazole,2-(3,5-bis-α-cumyl-2-hydroxyphenyl)-2H-benzotriazole,2-(3-tert-butyl-2-hydroxy-5-(2-(co-hydroxy-octa-(ethyleneoxy)carbonyl-ethyl)-,phenyl)-2H-benzotriazole,2-(3-dodecyl-2-hydroxy-5-methylphenyl)-2H-benzotriazole,2-(3-tert-butyl-2-hydroxy-5-(2-octyloxycarbonyl)ethylphenyl)-2H-benzotriazole,dodecylated 2-(2-hydroxy-5-methylphenyl)-2-H-benzotriazole,2-(3-tert-butyl-2-hydroxy-5-(2-octyloxycarbonylethyl)phenyl)-5-chloro-2H-benzotriazole,2-(3-tert-butyl-5-(2-(2-ethylhexyloxy)-carbonylethyl)-2-hydroxyphenyl)-5-chloro-2H-benzotriazole,2-(3-tert-butyl-2-hydroxy-5-(2-methoxycarbonylethyl)phenyl)-5-chloro-2H-benzotriazole,2-(3-tert-butyl-2-hydroxy-5-(2-methoxycarbonylethyl)phenyl)-2H-benzotriazole,2-(3-tert-butyl-5-(2-(2-ethylhexyloxy)carbonylethyl)-2-hydroxyphenyl)-2H-benzotriazole,2-(3-tert-butyl-2-hydroxy-5-(2-isooctyloxycarbonylethyl)phenyl-2H-benzotriazole,2,2′-methylene-bis(4-tert-octyl-(6-2H-benzotriazol-2-yl)phenol),2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole,2-(2-hydroxy-3-tert-octyl-5-α-cumylphenyl)-2H-benzotriazole,5-fluoro-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole,5-chloro-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole,5-chloro-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole,2-(3-tert-butyl-2-hydroxy-5-(2-isooctyloxycarbonylethyl)phenyl)-5-chloro-2H-benzotriazole,5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole,5-trifluoromethyl-2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole,5-trifluoromethyl-2-(2-hydroxy-3,5-di-tert-octylphenyl)-2H-benzo-triazole,methyl3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocinnamate,5-butylsulfonyl-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole,5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-tert-butylphenyl)-2H-benzotriazole,5-trifluoromethyl-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole,5-trifluoromethyl-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole,5-butylsulfonyl-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazoleand5-phenylsulfonyl-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole.

3.2. 2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy,4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2′,4′-trihydroxyand 2′-hydroxy-4,4′-dimethoxy derivatives.

3.3. Esters of substituted and unsubstituted benzoic acids, as forexample 4-tert-butyl-phenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoyl resorcinol, bis(4-tert-butylbenzoyl) resorcinol,benzoyl resorcinol, 2,4-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl3,5-di-tert-butyl-4-hydroxybenzoate, 2-methyl-4,6-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate.

3.4. Acrylates and malonates, for example, α-cyano-β,β-diphenylacrylicacid ethyl ester or isooctyl ester, α-carbomethoxy-cinnamic acid methylester, α-cyano-β-methyl-p-methoxy-cinnamic acid methyl ester or butylester, α-carbomethoxy-p-methoxy-cinnamic acid methyl ester,N-(β-carbomethoxy-β-cyanovinyl)-2-methyl-indoline, Sanduvor® PR 25,(Clariant), dimethyl p-methoxybenzylidenemalonate (CAS#7443-25-6), andSanduvor® PR 31 (Clariant), di-(1,2,2,6,6-pentamethylpiperid-in-4-yl)p-methoxybenzylidenemalonate (CAS #147783-69-5).

3.5. Oxamides, for example 4, 4′-dioctyloxyoxanilide,2,2′-diethoxyoxanilide, 2,2′-dioctyloxy-5,5′-di-tert-butoxanilide,2,2′-didodecyloxy-5,5′-di-tert-butoxanilide, 2-ethoxy-2′-ethyloxanilide,N,N′-bis(3-dimethylaminopropyl)oxamide,2-ethoxy-5-tert-butyl-2′-ethoxanilide and its mixture with2-ethoxy-2′-ethyl-5,4′-di-tert-butoxanilide, mixtures of o- andp-methoxy-disubtituted oxanilides and mixtures of o- andp-ethoxy-disubstituted oxanilides.

3.6. Tris-aryl-o-hydroxyphenyl-s-triazines, for example known commercialtris-aryl-o-hydroxyphenyl-s-triazines and triazines as disclosed in, WO96/28431, EP 434608, EP 941989, GB 2,317,893, U.S. Pat. Nos. 3,843,371;4,619,956; 4,740,542; 5,096,489; 5,106,891; 5,298,067; 5,300,414;5,354,794; 5,461,151; 5,476,937; 5,489,503; 5,543,518; 5,556,973;5,597,854; 5,681,955; 5,726,309; 5,942,626; 5,959,008; 5,998,116 and6,013,704, the entire contents of each of which are incorporated hereinby reference, for example4,6-bis-(2,4-dimethylphenyl)-2-(2-hydroxy-4-octyloxyphenyl)-s-triazine(Cyasorb® 1164, Cytec Corp.),4,6-bis-(2,4-dimethylphenyl)-2-(2,4-dihydroxyphenyl)-s-triazine,2,4-bis(2,4-dihydroxyphenyl)-6-(4-chlorophenyl)-s-triazine,2,4-bis[2-hydroxy-4-(2-hydroxpethoxy)phenyl]-6-(4-chlorophenyl)-s-triazine,2,4-bis[2-hydroxy-4-(2-hydroxy-4-(2-hydroxyethoxy)phenyl]-6-(2,4-dimethylphenyl)-s-triazine,2,4-bis[2-hydroxy-4-(2-hydroxyethoxy)phenyl]-6-(4-bromophenyl)-s-triazine,2,4-bis[2-hydroxy-4-(2-acetoxyethoxy)phenyl]-6-(4-chlorophenyl)-s-triazine,2,4-bis(2,4-dihydroxyphenyl)-6-(2,4-dimethylphenyl)-s-triazine,2,4-bis(4-biphenylyl)-6-(2-hydroxy-4-octyloxycarbonylethylideneoxyphenyl)-s-triazine,2-phenyl-4-[2-hydroxy-4-(3-sec-butyloxy-2-hydroxypropyloxy)phenyl]-6-[2-hydroxy-4-(3-sec-amyloxy-2-hydroxy-propyloxy)phenyl]-s-triazine,2,4-bis(2,4-dimethylphenyl)-6-[2-hydroxy-4-(3-benzyloxy-2-hydroxypropyloxy)phenyl]-s-triazine,2,4-bis(2-hydroxy-4-n-butyloxyphenyl)-6-(2,4-di-n-butyloxyphenyl)-s-triazine,2,4-bis(2,4-dimethylphenyl)-6-[2-hydroxy-4-(3-nonyloxy*-2-hydroxypropyloxy)-5-□-cumylphenyl]-s-triazine(* denotes a mixture of octyloxy, nonyloxy and decyloxy groups),methylenebis-{2,4-bis(2,4-dimethylphenyl)-6-[2-hydroxy-4-(3-butyloxy-2-hydroxypropoxy)phenyl]-s-triazine},methylene bridged dimer mixture bridged in the 3:5′, 5:5′ and 3:3′positions in a 5:4:1 ratio,2,4,6-tris(2-hydroxy-4-isooctyloxycarbonylsopropylideneoxy-phenyl)-s-triazine,2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-hexyloxy-5-α-cumylphenyl)-s-triazine,2-(2,4,6-trimethylphenyl)-4,6-bis[2-hydroxy-4-(3-butyloxy-2-hydroxypropyloxy)-phenyl]-s-triazine,2,4,6-tris[2-hydroxy-4-(3-sec-butyloxy-2-hydroxapropyloxy)phenyl]-s-triazine,mixture of4,6-bis-(2,4-dimethylphenyl)-2-(2-hydroxy-4-(3-dodecyloxy-2-hydroxypropoxy)-phenyl)-s-triazineand4,6-bis-(2,4-dimethylphenyl)-2-(2-hydroxy-4-(3-tridecyloxy-2-hydroxypropoxy)-phenyl)-s-triazine,Tinuvin® 400, Ciba Specialty Chemicals Corp.,4,6-bis-(2,4-dimethylphenyl)-2-(2-hydroxy-4-(3-(2-ethylhexyloxy)-2-hydroxypropoxy)-phenyl)-s-triazineand 4,6-diphenyl-2-(4-hexyloxy-2-hydroxyphenyl)-s-triazine.

4. Metal deactivators, as used herein are compounds which form stablecomplexes with metal ions and inhibit their reaction with peroxides, forexample, N,N′-diphenyloxamide, N-salicylal-N′-salicyloyl hydrazine,N,N′-bis(salicyloyl)hydrazine,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine,3-salicyloylamino-1,2,4-triazole, bis(benzylidene)oxalyl dihydrazide,oxanilide, isophthaloyl dihydrazide, sebacoyl bisphenylhydrazide,N,N′-diacetyladipoyl dihydrazide, N,N′-bis(salicyloyl)oxalyldihydrazide, N,N′-bis(salicyloyl)thiopropionyl dihydrazide.

5. Peroxide scavengers, for example, esters of β-thiodipropionic acid,for example the lauryl, stearyl, myristyl or tridecyl esters,mercaptobenzimidazole or the zinc salt of 2-mercaptobenzimidazole, zincdibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritoltetrakis(β-dodecylmercapto)propionate.

6. Hydroxylamines, for example, N,N-dihydrocarbylhydroxylamines selectedfrom the group consisting of N,N-dibenzylhydroxylamine,N,N-dimethyl-hydroxylamine, N,N-diethylhydroxylamine,N,N-bis(2-hydroxypropyl)hydroxylamine,N,N-bis(3-hydroxypropyl)hydroxylamine,N,N-bis(2-carboxyethyl)hydroxylamine,N,N-bis(benzylthiomethyl)hydroxylamine, N,N-dioctylhydroxylamine,N,N-dilaurylhydroxylamine, N,N-didodecylhydroxylamine,N,N-ditetradecylhydroxylamine, N,N-dihexadecylhydroxylamine,N,N-dioctadecylhydroxylamine, N-hexadecyl-N-tetradecylhydroxylamine,N-hexadecyl-N-heptadecylhydroxylamine,N-hexadecyl-N-octadecylhydroxylamine,N-heptadecyl-N-octadecylhydroxylamine,N-methyl-N-octadecylhydroxylamine, and N,N-di(hydrogenatedtallow)hydroxylamine. The hydroxylamine may be for example theN,N-di(alkyl)hydroxylamine produced by the direct oxidation ofN,N-di(hydrogenated tallow)amine. For example, the hydroxylamineprepared by direct hydrogen peroxide oxidation of bis(hydrogenatedtallow alkyl)amines, that is N,N-di(hydrogenated tallow)hydroxylamine,CAS#143925-92-2. N,N-di(hydrogenated tallow)hydroxylamine is prepared asin the working Examples of U.S. Pat. No. 5,013,510 the entire contentsof which are incorporated herein by reference.

7. Nitrones, for example, N-benzyl-α-phenyl-nitrone,N-ethyl-α-methyl-nitrone, N-octyl-α-heptyl-nitrone,N-lauryl-α-undecyl-nitrone, N-tetradecyl-α-tridcyl-nitrone,N-hexadecyl-α-pentadecyl-nitrone, N-octadecyl-α-heptadecyl-nitrone,N-hexadecyl-α-heptadecyl-nitrone, N-ocatadecyl-α-pentadecyl-nitrone,N-heptadecyl-α-heptadecyl-nitrone, N-octadecyl-α-hexadecyl-nitrone,nitrone derived from N,N-di(hydrogenated tallow)hydroxylamine.

8. Amine-N-oxides, for example Genox™ EP, a di(C₁₆-C₁₈)alkyl methylamine oxide, CAS#204933-93-7, Crompton Corporation.

9. Benzofuranones and indolinones, for example those disclosed in U.S.Pat. Nos. 4,325,863; 4,338,244; 5,175,312; 5,216,052; 5,252,643;5,369,159; 5,488,117; 5,356,966; 5,367,008; 5,428,162; 5,428,177;5,516,920; DE-A-4316611; DE-A-4316622; DE-A-4316876; EP-A-0589839 orEP-A-0591102 the entire contents of each of which are incorporatedherein by reference, or344-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butyl-benzofuran-2-one,5,7-di-tert-butyl-3-[4-(2-stearoyloxyethoxy)phenyl]benzofuran-2-one,3,3′-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)benzofuran-2-one],5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one,3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one,3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-tert-butyl-benzofuran-2-one,3-(3,4-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one,3-(2,3-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one.

10. Polyhydric alcohols, for example pentaerythritol and glycerol.

11. Basic co-stabilizers, for example, melamine, polyvinylpyrrolidone,dicyandiamide, triallyl cyanurate, urea derivatives, hydrazinederivatives, amines, polyamides and polyurethanes.

12. Nucleating agents, for example, inorganic substances such as talcum,metal oxides such as titanium dioxide or magnesium oxide, phosphates,carbonates or sulfates of, preferably, alkaline earth metals; organiccompounds such as mono- or polycarboxylic acids and the salts thereof,e.g. 4-tert-butylbenzoic acid, adipic acid, diphenylacetic acid, sodiumsuccinate or sodium benzoate, lithium benzoate, disodiumbicycle[2.2.1]heptane 2,3-dicarboxylate; organic phosphates and saltsthereof, e.g. sodium2,2′-methylenebis(4,6-di-tert-butylphenyl)phosphate, and polymericcompounds such as ionic copolymers (ionomers).

13. Clarifiers, for example substituted and unsubstituted bisbenzylidenesorbitols.

14. Fillers and reinforcing agents, for example, calcium carbonate,silicates, glass fibers, glass bulbs, asbestos, talc, wollastonite,nanoclays, kaolin, mica, barium sulfate, metal oxides and hydroxides,carbon black, graphite, wood flour and flours or fibers of other naturalproducts, synthetic fibers.

15. Dispersing Agents, as used herein are compounds which when added toa colloidal solution disperse the particles uniformly, such as, forexample, polyethylene oxide waxes or mineral oil.

16. Other additives, for example, plasticizers, lubricants, emulsifiers,pigments, rheology additives, catalysts, flow-control agents, opticalbrighteners, flame retardants, antistatic agents, antimicrobials andblowing agents.

In certain embodiments of the present invention the co-stabilizers areadded, for example, in concentrations of from about 0.0001% to about 50%by weight, about 0.0005% to about 20% by weight, about 0.001% to about10% by weight, from about 0.01% to about 5% by weight, from about 0.05%to about 1% by weight from about 0.1% to about 1% by weight based on theoverall weight of the polyolefin to be stabilized.

In certain other embodiments of the present invention the fillers andreinforcing agents, for example talc, calcium carbonate, mica or kaolin,are added to the polyolefins in concentrations of about 0.001% to about80% by weight, about 0.005% to about 60% by weight, about 0.01% to about40% by weight, of about 0.05% to about 20% by weight, of about 0.1% toabout 10% by weight, of about 0.5% to about 5% by weight, based on theoverall weight of the polyolefins to be stabilized.

In certain particular embodiments of the present invention the fillersand reinforcing agents, for example metal hydroxides, especiallyaluminum hydroxide or magnesium hydroxide, are added to the polyolefinsin concentrations of about 0.001% to about 80% by weight, about 0.005%to about 70% by weight, about 0.01% to about 60% by weight, about 0.1%to about 50% by weight about 0.5% to about 40% by weight about 1% toabout 20% by weight based on the overall weight of the polyolefins to bestabilized.

In certain particular embodiments of the present invention carbon blackas filler is added to the polyolefins in concentrations, judiciously, offrom about 0.001% to about 30% by weight, 0.005% to about 10% by weight,0.01% to about 5% by weight, of from about 0.05% to about 3% by weightof from about 0.1% to about 2% by weight of from about 0.1% to about 1%by weight based on the overall weight of the polyolefins to bestabilized.

In certain particular embodiments of the present invention glass fibersas reinforcing agents are added to the polyolefins in concentrations,judiciously, of from of about 0.001% to about 80% by weight, about0.005% to about 60% by weight, about 0.01% to about 40% by weight, ofabout 0.05% to about 20% by weight, of about 0.1% to about 10% byweight, based on the overall weight of the polyolefins to be stabilized.

The term “alkyl” as used herein means a saturated straight-chain,branched or cyclic hydrocarbon. When straight-chained or branched, analkyl group is typically C1-C8, more typically C1-C6; when cyclic, analkyl group is typically C3-C12, more typically C3-C7 alkyl ester.Examples of alkyl groups include methyl, ethyl, n-propyl, iso-propyl,n-butyl, sec-butyl and tert-butyl and 1,1-dimethylhexyl.

The term “alkoxy” as used herein is represented by —OR**, wherein R** isan alkyl group as defined above.

The term “acyl” as used herein is represented by —C(O)R**, wherein R**is an alkyl group as defined above.

The term “alkyl ester” as used herein means a group represented by—C(O)OR**, where R** is an alkyl group as defined above.

The term “aromatic group” used alone or as part of a larger moiety as in“aralkyl”, includes carbocyclic aromatic rings and heteroaryl rings. Theterm “aromatic group” may be used interchangeably with the terms “aryl”,“aryl ring” “aromatic ring”, “aryl group” and “aromatic group”.

Carbocyclic aromatic ring groups have only carbon ring atoms (typicallysix to fourteen) and include monocyclic aromatic rings such as phenyland fused polycyclic aromatic ring systems in which two or morecarbocyclic aromatic rings are fused to one another. Examples include1-naphthyl, 2-naphthyl, 1-anthracyl and 2-anthracyl. Also includedwithin the scope of the term “carbocyclic aromatic ring”, as it is usedherein, is a group in which an aromatic ring is fused to one or morenon-aromatic rings (carbocyclic or heterocyclic), such as in an indanyl,phthalimidyl, naphthimidyl, phenanthridinyl, or tetrahydronaphthyl,where the radical or point of attachment is on the aromatic ring.

The term “heteroaryl”, “heteroaromatic”, “heteroaryl ring”, “heteroarylgroup” and “heteroaromatic group”, used alone or as part of a largermoiety as in “heteroaralkyl” refers to heteroaromatic ring groups havingfive to fourteen members, including monocyclic heteroaromatic rings andpolycyclic aromatic rings in which a monocyclic aromatic ring is fusedto one or more other aromatic ring. Heteroaryl groups have one or morering heteroatoms. Examples of heteroaryl groups include 2-furanyl,3-furanyl, N-imidazolyl, 2-imidazolyl, 4-imidazolyl, 5-imidazolyl,3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 2-oxadiazolyl, 5-oxadiazolyl,2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 3-pyrazolyl, 4-pyrazolyl,1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 2-pyridyl, 3-pyridyl, 4-pyridyl,2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, 3-pyridazinyl, 2-thiazolyl,4-thiazolyl, 5-thiazolyl, 2-triazolyl, 5-triazolyl, tetrazolyl,2-thienyl, 3-thienyl, carbazolyl, 2-benzothienyl, 3-benzothienyl,2-benzofuranyl, 3-benzofuranyl, 2-indolyl, 3-indolyl, 2-quinolinyl,3-quinolinyl, 2-benzothiazole, 2-benzooxazole, 2-benzimidazole,2-quinolinyl, 3-quinolinyl, 1-isoquinolinyl, 3-quinolinyl, 1-isoindolyland 3-isoindolyl. Also included within the scope of the term“heteroaryl”, as it is used herein, is a group in which an aromatic ringis fused to one or more non-aromatic rings (carbocyclic orheterocyclic), where the radical or point of attachment is on thearomatic ring.

The term “heteroatom” means nitrogen, oxygen, or sulfur and includes anyoxidized form of nitrogen and sulfur, and the quaternized form of anybasic nitrogen. Also the term “nitrogen” includes a substitutablenitrogen of a heteroaryl or non-aromatic heterocyclic group. As anexample, in a saturated or partially unsaturated ring having 0-3heteroatoms selected from oxygen, sulfur or nitrogen, the nitrogen maybe N (as in 3,4-dihydro-2H-pyrrolyl), NH (as in pyrrolidinyl) or NR″ (asin N-substituted pyrrolidinyl), wherein R″ is a suitable substituent forthe nitrogen atom in the ring of a non-aromatic nitrogen-containingheterocyclic group, as defined below.

An “aralkyl group”, as used herein is an alkyl groups substituted withan aryl group as defined above.

An optionally substituted aryl group as defined herein may contain oneor more substitutable ring atoms, such as carbon or nitrogen ring atoms.Examples of suitable substituents on a substitutable ring carbon atom ofan aryl group include —OH, C1-C3 alkyl, C1-C3 haloalkyl, —NO₂, C1-C3alkoxy, C1-C3 haloalkoxy, —CN, —NH₂, C1-C3 alkylamino, C1-C3dialkylamino, —C(O)NH₂, —C(O)NH(C1-C3 alkyl), —C(O)(C1-C3 alkyl),—NHC(O)H, —NHC(O)(C1-C3 alkyl), —C(O)N(C1-C3 alkyl)₂, —NHC(O)O—(C1-C3alkyl), —C(O)OH, —C(O)O—(C1-C3 alkyl), —NHC(O)NH₂, —NHC(O)NH(C1-C3alkyl), —NHC(O)N(C1-C3 alkyl)₂, —SO₂NH₂—SO₂NH(C1-C3alkyl),—SO₂N(C1-C3alkyl)₂, NHSO₂H or NHSO₂(C1-C3 alkyl). Preferred substituentson aryl groups are as defined throughout the specification. In certainembodiments optionally substituted aryl groups are unsubstituted

Examples of suitable substituents on a substitutable ring nitrogen atomof an aryl group include C1-C3 alkyl, NH₂, C1-C3 alkylamino, C1-C3dialkylamino, —C(O)NH₂, —C(O)NH(C1-C3 alkyl), —C(O)(C1-C3 alkyl),—CO₂R**, —C(O)C(O)R**, —C(O)CH₃, —C(O)OH, —C(O)O—(C1-C3 alkyl),—SO₂NH₂—SO₂NH(C1-C3 alkyl), —SO₂N(C1-C3alkyl)₂, NHSO₂H, NHSO₂(C1-C3alkyl), —C(═S)NH₂, —C(═S)NH(C1-C3 alkyl), —C(═S)N(C1-C3 alkyl)₂,—C(═NH)—N(H)₂, —C(═NH)—NH(C1-C3 alkyl) and —C(═NH)—N(C1-C3 alkyl)₂,

An optionally substituted alkyl group as defined herein may contain oneor more substituents. Examples of suitable substituents for an alkylgroup include those listed above for a substitutable carbon of an aryland the following: ═O, ═S, ═NNHR**, ═NN(R**)₂, ═NNHC(O)R**, ═NNHCO₂(alkyl), ═NNHSO₂ (alkyl), ═NR**, spiro cycloalkyl group or fusedcycloalkyl group. R** in each occurrence, independently is —H or C1-C6alkyl. Preferred substituents on alkyl groups are as defined throughoutthe specification. In certain embodiments optionally substituted alkylgroups are unsubstituted.

A “spiro cycloalkyl” group is a cycloalkyl group which shares one ringcarbon atom with a carbon atom in an alkylene group or alkyl group,wherein the carbon atom being shared in the alkyl group is not aterminal carbon atom.

Without wishing to be bound by any theory or limited to any mechanism itis believed that macromolecular antioxidants and polymericmacromolecular antioxidants of the present invention exploit thedifferences in activities (ks, equilibrium constant) of, for example,homo- or hetero-type antioxidant moieties. Antioxidant moieties include,for example, hindered phenolic groups, unhindered phenolic groups,aminic groups and thioester groups, etc. of which there can be one ormore present in each macromolecular antioxidant molecule. As used hereina homo-type antioxidant macromolecule comprises antioxidant moietieswhich are all same, for example, hindered phenolic, —OH groups. As usedherein a hetero-type antioxidant macromolecule comprises at least onedifferent type of moiety, for example, hindred phenolic and aminicgroups in the one macromolecule.

This difference in activities can be the result of, for example, thesubstitutions on neighboring carbons or the local chemical or physicalenvironment (for example, due to electrochemical or stereochemicalfactors) which can be due in part to the macromolecular nature ofmolecules.

In one embodiment of the present invention, a series of macromolecularantioxidant moieties of the present invention with different chemicalstructures can be represented by W1H, W2H, W3H, . . . to WnH. In oneembodiment of the present invention, two types of antioxidant moietiesof the present invention can be represented by: W1H and W2H. In certainembodiments W1H and W2H can have rate constants of k1 and k2respectively. The reactions involving these moieties and peroxylradicals can be represented as:

where ROO. is a peroxyl radical resulting from, for example, initiationsteps involving oxidation activity, for example:RH→R.+H.  (3)R.+O2→ROO.  (4)

In one particular embodiment of the present invention k1>>k2 inequations (1) and (2). As a result, the reactions would take place insuch a way that there is a decrease in concentration of W1. freeradicals due their participation in the regeneration of active moietyW2H in the molecule according equation (5):W1.+W2H→W1H+W2.  (5)(transfer equilibrium)

This transfer mechanism may take place either in intra-orinter-molecular macromolecules. The transfer mechanism (5) could takeplace between moieties residing on the same macromolecule (intra-type)or residing on different macromolecules (inter-type).

In certain embodiments of the present invention, the antioxidantproperties described immediately above (equation 5) of themacromolecular antioxidants and polymeric macromolecular antioxidants ofthe present invention result in advantages including, but not limitedto:

-   -   a) Consumption of free radicals W1. according to equation (5)        can result in a decrease of reactions of W1. with hydroperoxides        and hydrocarbons (RH).    -   b) The regeneration of W1H provides extended protection of        materials. This is a generous benefit to sacrificial type of        antioxidants that are used today. Regeneration of W1H assists in        combating the oxidation process The increase in the        concentration of antioxidant moieties W1H (according to        equation 5) extends the shelf life of materials.

In certain embodiments of the present invention, the following items areof significant interest for enhanced antioxidant activity in the designof the macromolecular antioxidants and polymeric macromolecularantioxidants of the present invention:

-   -   a) The activity of proposed macromolecular antioxidant is        dependent on the regeneration of W1H in equation (5) either        through inter- or intra-molecular activities involving homo- or        hetero-type antioxidant moieties.    -   b) Depending on the rates constants of W1H and W2H it is        possible to achieve performance enhancements by many multiples        and not just incremental improvements.

In certain embodiments of the present invention, more than two types ofantioxidant moieties with different rate constants are used in themethods of the present invention.

In certain embodiments, the present invention pertains to the use of thedisclosed compositions to inhibit oxidation in an oxidizable materialsuch as for example a polyolefin.

For purposes of the present invention, a method of “inhibitingoxidation” is a method that inhibits the propagation of a freeradical-mediated process. Free radicals can be generated by heat, light,ionizing radiation, metal ions and some proteins and enzymes. Inhibitingoxidation also includes inhibiting reactions caused by the presence ofoxygen, ozone or another compound capable of generating these gases orreactive equivalents of these gases.

As used herein the term “oxidizable material” is any material which issubject to oxidation by free-radicals or oxidative reaction caused bythe presence of oxygen, ozone or another compound capable of generatingthese gases or reactive equivalents thereof. In particular theoxidizable material is a polyolefin, a mixture of polyolefins asubstituted polyolefin, (polyacrylates, polymethacrylates) andcopolymers of polyolefins as defined above.

The entire teachings of each of the following applications areincorporated herein by reference:

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EXEMPLIFICATION

Polyolefin samples have been stabilized with selective additivesdescribed in this disclosure using extrusion methods. These stabilizedpolyolefins have been tested for their performance using techniques suchas melt flow index, gas fading, oxidative induction time (OIT) (FIG. 1)and yellowness index (YI) (FIG. 2).

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

1. A composition comprising: a) a polyolefin or a mixture ofpolyolefins; b) an antioxidant selected from the group consisting of:

and c) at least one additive selected from the group consisting of: i) aphosphorus stabilizer selected from the group consisting of triphenylphosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites,tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite,distearyl pentaerythritol diphosphite,tris(2,4-di-tert-butylphenyl)phosphite, diisodecyl pentaerythritoldiphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite,bisisodecyloxy-pentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tri-tert-butylphenyl)pentaerythritol diphosphite, tristearylsorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl)4,4′-biphenylene-diphosphonite,6-isooctyloxy-2,4,8,10-tetra-tert-butyl-dibenzo[d,f][1,3,2]dioxaphosphepin,6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenzo[d,g][1,3,2]dioxaphosphocin,bis(2,4-di-tert-butyl-6-methylphenyl)methyl phosphite,bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite,(2,4,6-tri-tert-butylphenyl) 2-butyl-2-ethyl-1,3-propanediol phosphate,bis(2,4-di-cumylphenyl)pentaerythritol diphosphite and a compoundrepresented by the following structural formula:

ii) at least one acid stabilizer selected from the group consisting ofzinc oxide, calcium lactate, natural and synthetic hydrotalcites,natural and synthetic hydrocalumites, and alkali metal salts andalkaline earth metal salts of higher fatty acids, calcium stearate, zincstearate, magnesium behenate, magnesium stearate, sodium stearate,sodium ricinoleate and potassium palmitate, antimony pyrocatecholate,zinc pyrocatecholate and combinations thereof; and iii) at least oneco-stabilizer selected from the group consisting of an antioxidant, ahindered amine stabilizer, an ultraviolet absorber, a metal deactivator,a peroxide scavenger, a hydroxylamine, a nitrone, an amine-N-oxide, abenzafuranone, an indolinone, a polyhydric alcohol, a basicco-stabilizer, a nucleating agent, a clarifier, a filler, a dispersingagent, a plasticizer, a lubricant, an emulsifier, a pigment, a rheologyadditive, a catalyst, a flow-control agent, an optical brightener, aflame retardant, an antistatic agent, an antimicrobial and blowingagents.
 2. The composition of claim 1 wherein the additive is at leastone phosphorus stabilizer selected from the group consisting oftris(2,4-di-tert-butylphenyl)phosphite,bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylene-diphosphonite,(2,4,6-tri-tert-butylphenyl) 2-butyl-2-ethyl-1,3-propanediol phosphateand bis(2,4-di-cumylphenyl)pentaerythritol diphosphite.
 3. Thecomposition of claim 2 wherein the antioxidant is in a concentrationrange from 0.0001% to 10% and the phosphorus stabilizer is in aconcentration range 0.01% to 5%.
 4. The composition of claim 2, whereinthe additive further includes at least one co-stabilizer selected fromthe group consisting of a hindered amine stabilizer, an ultravioletabsorber, a metal deactivator, a peroxide scavenger and a hydroxylamine.5. The composition of claim 1 wherein the additive is at least one acidstabilizer selected from the group consisting of zinc oxide, and alkalimetal salts and alkaline earth metal salts of higher fatty acids,calcium stearate, zinc stearate, magnesium behenate, magnesium stearate,sodium stearate, sodium ricinoleate and potassium palmitate, antimonypyrocatecholate and zinc pyrocatecholate.
 6. The composition of claim 5wherein the antioxidant is in a concentration range from 0.0001% to 10%and the acid stabilizer is in a concentration range 0.005% to 5%.
 7. Thecomposition of claim 5, wherein the additive further includes at leastone co-stabilizer selected from the group consisting of a hindered aminestabilizer, an ultraviolet absorber, a metal deactivator, a peroxidescavenger and a hydroxylamine.
 8. The composition of claim 1 wherein theadditive is at least one phosphorus stabilizer selected from the groupconsisting of tris(2,4-di-tert-butylphenyl)phosphite,bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylene-diphosphonite,(2,4,6-tri-tert-butylphenyl) 2-butyl-2-ethyl-1,3-propanediol phosphateand bis(2,4-di-cumylphenyl)pentaerythritol diphosphite and an acidstabilizer selected from the group consisting of at least one acidstabilizer selected from the group consisting of zinc oxide, calciumlactate, natural and synthetic hydrotalcites, natural and synthetichydrocalumites, and alkali metal salts and alkaline earth metal salts ofhigher fatty acids, calcium stearate, zinc stearate, magnesium behenate,magnesium stearate, sodium stearate, sodium ricinoleate and potassiumpalmitate, antimony pyrocatecholate and zinc pyrocatecholate.
 9. Thecomposition of claim 7, wherein the additive further includes at leastone co-stabilizer selected from the group consisting of a hindered aminestabilizer, an ultraviolet absorber, a metal deactivator, a peroxidescavenger and a hydroxylamine.
 10. The composition of claim 1, whereinthe polyolefin is at least one member selected from the group consistingof polypropylene, polyisobutylene, polybut-1-ene,poly-4-methylpent-1-ene, polyisoprene, polybutadiene, cyclopentene,norbornene, polyethylene, high density polyethylene (HDPE), high densityand high molecular weight polyethylene (HDPE-HMW), high density andultrahigh molecular weight polyethylene (HDPE-UHMW), medium densitypolyethylene (MDPE), low density polyethylene (LDPE), linear low densitypolyethylene (LLDPE), very low density polypropylene VLDPE), ultra lowdensity polypropylene (ULDPE), mixtures of polypropylene withpolyisobutylene, mixtures of polypropylene with polyethylene,ethylene/propylene copolymers, linear low density polyethylene (LLDPE)and mixtures of linear low density polyethylene with low densitypolyethylene (LDPE), propylene/but-1-ene copolymers,propylene/isobutylene copolymers, ethylene/but-1-ene copolymers,ethylene/hexene copolymers, ethylene/methylpentene copolymers,ethylene/heptene copolymers, ethylene/octene copolymers,propylene/butadiene copolymers, isobutylene/isoprene copolymers,ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylatecopolymers, ethylene/vinyl acetate copolymers,polypropylene/ethylene-propylene copolymers, LDPE/ethylene-vinyl acetatecopolymers (EVA), LDPE/ethylene-acrylic acid copolymers (EAA),LLDPE/EVA, LLDPE/EAA, ethylene-propylene-diene monomer copolymers(EPDM), copolymers of ethylene with higher alpha-olefins, polybutadiene,polyisoprene, styrene-butadiene copolymers, hydrogenatedstyrene-butadiene copolymers, styrene-isoprene copolymers, hydrogenatedstyrene-isoprene copolymers.
 11. The composition of claim 1, wherein theantioxidant is:


12. The composition of claim 1, wherein the antioxidant is:


13. A method of preventing oxidation in a polyolefin or a mixture ofpolyolefins comprising combining the polyolefin or mixture ofpolyolefins with: a) an antioxidant represented by the followingstructural formula:

and b) at least one additive selected from the group consisting of: i)at least one phosphorus stabilizer selected from the group consisting oftriphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkylphosphites, tris(nonylphenyl)phosphite, trilauryl phosphite,trioctadecyl phosphite, distearyl pentaerythritol diphosphite,tris(2,4-di-tert-butylphenyl)phosphite, diisodecyl pentaerythritoldiphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite,bisisodecyloxy-pentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tri-tert-butylphenyl)pentaerythritol diphosphite, tristearylsorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl)4,4′-biphenylene-diphosphonite,6-isooctyloxy-2,4,8,10-tetra-tert-butyl-dibenzo[d,f][1,3,2]dioxaphosphepin,6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenzo[d,g][1,3,2]dioxaphosphocin,bis(2,4-di-tert-butyl-6-methylphenyl)methyl phosphite,bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite(2,4,6-tri-tert-butylphenyl) 2-butyl-2-ethyl-1,3-propanediol phosphate,bis(2,4-di-cumylphenyl)pentaerythritol diphosphite and a compoundrepresented by the following structural formula:

ii) at least one acid stabilizer selected from the group consisting ofzinc oxide, calcium lactate, natural and synthetic hydrotalcites,natural and synthetic hydrocalumites, and alkali metal salts andalkaline earth metal salts of higher fatty acids, calcium stearate, zincstearate, magnesium behenate, magnesium stearate, sodium stearate,sodium ricinoleate and potassium palmitate, antimony pyrocatecholate,zinc pyrocatecholate and combinations thereof; and iii) at least oneco-stabilizer selected from the group consisting of an antioxidant, ahindered amine stabilizer, an ultraviolet absorber, a metal deactivator,a peroxide scavenger, a hydroxylamine, a nitrone, an amine-N-oxide, abenzafuranone, an indolinone, a polyhydric alcohol, a basicco-stabilizer, a nucleating agent, a clarifier, a filler, a dispersingagent, a plasticizer, a lubricant, an emulsifier, a pigment, a rheologyadditive, a catalyst, a flow-control agent, an optical brightener, aflame retardant, an antistatic agent, an antimicrobial and blowingagents.
 14. The method of claim 13 wherein the additive is at least onephosphorus stabilizer selected from the group consisting oftris(2,4-di-tert-butylphenyl)phosphite,bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylene-diphosphonite,(2,4,6-tri-tert-butylphenyl) 2-butyl-2-ethyl-1,3-propanediol phosphateand bis(2,4-di-cumylphenyl)pentaerythritol diphosphite.
 15. The methodof claim 14 wherein the antioxidant is in a concentration range from0.0001% to 10% and the phosphorus stabilizer is in a concentration range0.01% to 5%.
 16. The method of claim 14, wherein the additive furtherincludes at least one co-stabilizer selected from the group consistingof a hindered amine stabilizer, an ultraviolet absorber, a metaldeactivator, a peroxide scavenger and a hydroxylamine.
 17. The method ofclaim 13 wherein the additive is at least one acid stabilizer selectedfrom the group consisting zinc oxide, and alkali metal salts andalkaline earth metal salts of higher fatty acids, calcium stearate, zincstearate, magnesium behenate, magnesium stearate, sodium stearate,sodium ricinoleate and potassium palmitate, antimony pyrocatecholate andzinc pyrocatecholate.
 18. The method of claim 17 wherein the antioxidantis in a concentration range from 0.0001% to 10% and the acid stabilizeris in a concentration range 0.005% to 5%.
 19. The method of claim 17,wherein the additive further includes at least one co-stabilizerselected from the group consisting of a hindered amine stabilizer, anultraviolet absorber, a metal deactivator, a peroxide scavenger and ahydroxylamine.
 20. The method of claim 13 wherein the additive is atleast one phosphorus stabilizer selected from the group consisting oftris(2,4-di-tert-butylphenyl)phosphite,bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylene-diphosphonite,(2,4,6-tri-tert-butylphenyl) 2-butyl-2-ethyl-1,3-propanediol phosphateand bis(2,4-di-cumylphenyl)pentaerythritol diphosphite and an acidstabilizer selected from the group consisting of at least one acidstabilizer selected from the group consisting of zinc oxide, calciumlactate, natural and synthetic hydrotalcites, natural and synthetichydrocalumites, and alkali metal salts and alkaline earth metal salts ofhigher fatty acids, calcium stearate, zinc stearate, magnesium behenate,magnesium stearate, sodium stearate, sodium ricinoleate and potassiumpalmitate, antimony pyrocatecholate and zinc pyrocatecholate.
 21. Themethod of claim 20, wherein the additive further includes at least oneco-stabilizer selected from the group consisting of a hindered aminestabilizer, an ultraviolet absorber, a metal deactivator, a peroxidescavenger and a hydroxylamine.
 22. The method of claim 13, wherein thepolyolefin is at least one member selected from the group consisting ofpolypropylene, polyisobutylene, polybut-1-ene, poly-4-methylpent-1-ene,polyisoprene, polybutadiene, cyclopentene, norbornene, polyethylene,high density polyethylene (HDPE), high density and high molecular weightpolyethylene (HDPE-HMW), high density and ultrahigh molecular weightpolyethylene (HDPE-UHMW), medium density polyethylene (MDPE), lowdensity polyethylene (LDPE), linear low density polyethylene (LLDPE),very low density polypropylene (VLDPE) ultra low density polypropylene,(ULDPE), mixtures of polypropylene with polyisobutylene, mixtures ofpolypropylene with polyethylene, ethylene/propylene copolymers, linearlow density polyethylene (LLDPE) and mixtures of linear low densitypolyethylene with low density polyethylene (LDPE), propylene/but-1-enecopolymers, propylene/isobutylene copolymers, ethylene/but-1-enecopolymers, ethylene/hexene copolymers, ethylene/methylpentenecopolymers, ethylene/heptene copolymers, ethylene/octene copolymers,propylene/butadiene copolymers, isobutylene/isoprene copolymers,ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylatecopolymers, ethylene/vinyl acetate copolymers,polypropylene/ethylene-propylene copolymers, LDPE/ethylene-vinyl acetatecopolymers (EVA), LDPE/ethylene-acrylic acid copolymers (EAA),LLDPE/EVA, LLDPE/EAA, ethylene-propylene-diene monomer copolymers(EPDM), copolymers of ethylene with higher alpha-olefins, polybutadiene,polyisoprene, styrene-butadiene copolymers, hydrogenatedstyrene-butadiene copolymers, styrene-isoprene copolymers, hydrogenatedstyrene-isoprene copolymers.
 23. The method of claim 13, wherein theantioxidant is:


24. The method of claim 13, wherein the antioxidant is: